Series 23

No. 18

Health Aspects

of Pregnancy

and Childbirth:

United States, 1982–88

August 1995

Vital and

Health Statistics

From the CENTERS FOR DISEASE CONTROL AND PREVENTION / National Center for Health Statistics

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Public Health Service

Centers for Disease Control and Prevention

National Center for Health Statistics
Copyright Information

All material appearing in this report is in the public domain and may be

reproduced or copied without permission; citation as to source, however, is

appreciated.

Suggested Citation

Chandra, A. Health aspects of pregnancy and childbirth: United States,

1982–88. National Center for Health Statistics. Vital Health Stat 23(18). 1995.

Library of Congress-in-Publication Data

Chandra, Anjani.

Health aspects of pregnancy and childbirth, United States, 1982–88 / Anjani

Chandra.

p. cm. — (Vital and health statistics. Series 23, Data from the national survey

of family growth ; no. 18) (DHHS publication ; no. (PHS) 95-1994)

Includes bibliographical references.

ISBN 0-8406-0509-9

1. Prenatal care—United States—Statistics. 2. Birth weight, Low—United

States—Statistics. 3. Pregnant women—Tobacco use—United

States—Statistics. 4. Pregnant women—Alcohol use−United States—Statistics.

5. Childbirth—Economic aspects—United States—Statistics. [1. United

States—Statistics, Medical.] I. Title. II. Series. III. Series: DHHS publication ;

no. (PHS) 95-1994.

RG960.C48 1995

302.1'982'00973—dc20 95-32301

CIP
Health Aspects

of Pregnancy

and Childbirth:

United States, 1982–88

Series 23:

Data From the National Survey

of Family Growth

No. 18

Statistics collected in 1988 are presented on the timing of the first prenatal

visit, the source of prenatal care, smoking and alcohol use during

pregnancy, low birthweight, and how delivery was paid for. The data are

shown by race and characteristics of the mother and the pregnancy.

Trends between 1982 and 1988 are also presented.

Hyattsville, Maryland

August 1995

DHHS Publication No. (PHS) 95-1994

Vital and

Health Statistics

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Public Health Service

Centers for Disease Control and Prevention

National Center for Health Statistics
National Center for Health Statistics

Jack R. Anderson, Acting Director

Jennifer H. Madans, Ph.D., Acting Deputy Director

Jacob J. Feldman, Ph.D., Associate Director for Analysis,

Epidemiology, and Health Promotion

Gail F. Fisher, Ph.D., Associate Director for Planning and

Extramural Programs

Peter L. Hurley, Associate Director for Vital and Health

Statistics Systems

(Vacant), Associate Director for International Statistics

Stephen E. Nieberding, Associate Director for

Management

Charles J. Rothwell, Associate Director for Data

Processing and Services

Monroe G. Sirken, Ph.D., Associate Director for Research

and Methodology

Division of Vital Statistics

Mary Anne Freedman, Director

James A. Weed, Ph.D., Deputy Director

William D. Mosher, Ph.D., Chief, Family Growth Survey

Branch

Joseph D. Farrell, Chief, Systems and Programming Branch

Robert A. Armstrong, Acting Chief, Statistical Resources

Branch

Cooperation of the U.S. Bureau of the Census

Cycle IV of the National Survey of Family Growth, 1988, was supported in part by

the National Institute of Child Health and Human Development, National Institutes of

Health, and the Office of Population Affairs, Office of the Assistant Secretary of

Health. Both of these agencies also participated in the questionnaire and survey design.
Dr. London set the highest of standards for her

for 7 years the National Survey of Family Growth reape

of that commitment to quality.

Her integrity, dedication, and expertise fostered an at

collegiality and learning in which it was a delight 

Kathy’s generous spirit and unique perspectives are de
Contents

Introduction............................................................................................. 1

Summary of principal findings.............................................................................. 3

Timing of first prenatal visit ............................................................................. 3

Source of most prenatal care............................................................................. 3

Cigarette smoking during pregnancy ...................................................................... 4

Drinking during pregnancy .............................................................................. 4

Low birthweight....................................................................................... 5

Source of payment for delivery........................................................................... 5

Source and limitations of the data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Comparisons with other data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Findings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Timing of the first prenatal visit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Source of most prenatal care. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Cigarette smoking during pregnancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Drinking during pregnancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Smoking and drinking during pregnancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Low birthweight. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Source of payment for delivery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

List of detailed tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Appendixes

I. Technical notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

II. Definitions of terms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

III. Items on the 1988 National Survey of Family Growth questionnaire related to health aspects of pregnancy and

childbirth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Figures

1. Percent of mothers receiving prenatal care in the first trimester, by race of mother and marital status: United States,

1984–88......................................................................................... 3

2. Percent of mothers receiving prenatal care in the first trimester, by marital status of mother and year of birth of child:

United States .................................................................................... 5

3. Percent of mothers receiving prenatal care for a birth in 1984–88 and who received most prenatal care from a private

physician, by race and poverty level income: United States................................................ 5

4. Percent of women who reported any amount of cigarette smoking during their most recent pregnancy, by race and

education: United States, 1988 ...................................................................... 5

5. Percent of ever-pregnant women who smoked during their most recent pregnancy, by education and year of pregnancy

outcome: United States ............................................................................. 7

6. Percent of ever-pregnant women who drank once a month or more during their most recent pregnancy, by race and

education: United States, 1988 ...................................................................... 7

v
7. Percent of most recent single live births to women 15–44 years of age that were low birthweight, by race and number

of cigarettes smoked per day during pregnancy: United States, 1988 ........................................ 8

8. Percent of live births in 1984–88 that were paid for, in whole or part, from specified sources, by race of mother: United

States ........................................................................................... 8

9. Percent distribution of most recent live births (1984–88) by source of payment for delivery and marital status: United

States ........................................................................................... 9

10. Percent of deliveries paid in whole or in part by Medicaid, by age of mother and year of birth: United States ...... 9

Text tables

A. Number of live births to women 15–44 years of age and percent having first prenatal visit within first trimester of

pregnancy, by selected characteristics of the birth and mother: United States, 1979–82 and 1984–88 .............. 4

B. Number of women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and

percent who reported any amount of cigarette smoking during pregnancy, by year pregnancy ended and selected

characteristics of the pregnancy and mother: United States ................................................ 6

C. Number of women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and

percent distribution by whether they smoked cigarettes or drank alcohol during pregnancy, according to selected

characteristics of the pregnancy and mother: United States, 1988 ........................................... 7

D. Number of women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and

percent who reported drinking at all during pregnancy, by selected characteristics of the pregnancy and mother: United

States, 1982 and 1988 .............................................................................. 8

E. Number of live birth deliveries to women 15–44 years of age and percent paid by private insurance or Medicaid, by

selected characteristics of the birth and mother: United States, 1979–82 and 1984–88 .......................... 9

Symbols

- - - Data not available

. . . Category not applicable

– Quantity zero

0.0 Quantity more than zero but less than

0.05

Z Quantity more than zero but less than

500 where the numbers are rounded to

thousands

* Figure does not meet standards of

reliability or precision (see Technical

notes)

vi
Health Aspects of Pregnancy

and Childbirth

by Anjani Chandra, Ph.D., Division of Vital Statistics

Introduction

During the 20th century, infant mortality rates in the

United States have fallen dramatically, from 100 infant deaths

per 1,000 live births in 1900, to 23 in 1960, to 9 in 1990 (1–3).

In 1900, most infant deaths were due to infectious causes and

occurred after the neonatal period. In recent years, however,

neonatal deaths (those within the first 28 days of life) have

accounted for the majority of infant deaths (4–5). Low birth

weight is the key determinant of neonatal death. Although the

survival of low birth weight babies has markedly improved in

recent decades (6), the prevalence of low birth weight itself

has not declined comparably with infant mortality rates (1,2,7).

Given that the improved survival of low birth weight babies

has chiefly been tied to expensive, recent developments in

perinatal medicine, health care dollars would be saved and

later complications would be prevented if fewer births were

low birth weight (3,8).

Racial and ethnic group disparities persist in low birth

weight and infant mortality, even as overall death rates move

toward the Year 2000 national objective of 7 infant deaths per

1,000 live births (3,7,9). These disparities are largely attributable to continuing social and economic differentials in health

status among subgroups of the population (8,10–13). The

United States, though currently ranked 24th in infant mortality

rate (14), is not alone among industrialized nations with regard

to socioeconomic and racial-ethnic disparities. Despite their

lower overall infant mortality rates, countries such as Sweden,

Australia, France, and England also face large gaps in pregnancy outcomes and other health indices among groups of

varying socioeconomic status (15–19).

The prevention of low birthweight will yield marked

reductions in perinatal morbidity and mortality, as well as

reductions in developmental deficits and health problems later

in childhood (8,13,20,21). Although there may be debate over

the specific mechanisms, there is general consensus that the

most effective means of reducing rates of low birthweight, and

thereby narrowing the racial and ethnic gaps in maternal and

child health status in the United States, would include the

following strategies: improving access to and quality of prenatal care; reducing prenatal smoking, drinking, and substance

abuse; and narrowing disparities in nutritional status and other

areas of health (3,8,13).

To monitor the Nation’s progress toward these goals,

reliable national data must be collected. The National Survey

of Family Growth (NSFG), a periodic survey conducted by the

National Center for Health Statistics, is designed to provide

information on fertility, family planning, and aspects of maternal, child, and reproductive health that are closely related to

childbearing. The NSFG offers several key health measures

that are useful in assessing the risk of poor pregnancy

outcomes among various groups in the United States. This

report follows the precedent set by the first comprehensive

presentation of NSFG data on health aspects of pregnancy and

childbirth, which was based on the 1982 cycle (22). Health

and pregnancy data from the 1988 NSFG are presented, with

an emphasis on correlates of low birthweight.

The pregnancy-related health measures presented in this

report include:

+ The number of months women had been pregnant when

they began receiving prenatal care for that pregnancy

(tables 1–6).

+ Whether women received their prenatal care for that

pregnancy from a private doctor, a hospital clinic, or

another kind of clinic (tables 7–12).

+ Whether women smoked during their most recent pregnancy and, if so, how much they smoked (tables 13–18).

+ Whether women drank alcoholic beverages during their

most recent pregnancy and, if so, how often they drank

(tables 19–20).

+ The proportion of babies born at low birthweight (2,500

grams or less) (tables 21–22).

+ Trends in the proportion of deliveries that were low birthweight (tables 23–24).

+ How deliveries were paid for (sources of payment) (tables

25–32).

Data in these tables are presented for women of all races

and separately for white (n = 5,354) and black (n = 2,771)

women. Although some tables show results separately for

Hispanic women, the sample size for Hispanic women in the

NSFG sample (n = 641) was neither large enough to provide

separate tables for this group, nor could Hispanic women be

stratified by race. Data on Hispanic women are compared with

data for non-Hispanic white and non-Hispanic black women.

Data are presented on prenatal care, low birthweight, and

how delivery was paid for (tables 1–12 and 21–30). The unit

of analysis is the pregnancy or birth. Women who had more

than one pregnancy are included once for each pregnancy, and

women who had never been pregnant are excluded. Although

‘‘women’’ is sometimes used in the text discussing these

1
tables, the reader should note that these tables refer to

pregnancies or births.

In tables 13–20, data are presented on smoking and

drinking during pregnancy. These data were only available for

the most recent pregnancy or birth for each woman. Therefore,

in these tables, women with multiple pregnancies are represented once. To show the trends in payment since the 1982

NSFG, tables 31–32 present data on the source of payment for

delivery for the most recent birth occurring between 1984–88.

Because the form of payment is likely to be similar for each of

a woman’s births, she is included only once to avoid overrepresentation of women with multiple births.

Although the NSFG is not the only source of national data

on health aspects of pregnancy and childbirth, it offers a

unique range of explanatory variables that permit a more

complete description of trends in the fertility experience of

American women. The data shown here, taken together with

reports from other national data sources, are useful for evaluating the adequacy of medical care women receive during

pregnancy, the sources they use to obtain and pay for prenatal

care and obstetric services, certain health practices during

pregnancy, and birth weight. A further strength of the NSFG is

that it started collecting certain data, such as prenatal care and

smoking during pregnancy, before these data were added to

the birth certificate. Other variables, such as wantedness of

pregnancies, income, and source of payment, are still not

available from vital statistics. The NSFG remains the primary

source of trend data related to pregnancy and childbirth

throughout the 1960’s–1980’s.

Other aspects of reproductive health have been addressed

in several previous NSFG reports, including infertility (23),

contraception (24), unwanted childbearing (25), pelvic inflammatory disease (26), testing for sexually transmitted diseases

(27), and other women’s health screening (28).

2
Summary of principal

findings

There are large differences by race and Hispanic origin in

many of the health measures discussed in this report. Therefore, data are presented separately for pregnancies of white,

black, and Hispanic women. Differences between Hispanic

women, non-Hispanic white women, and non-Hispanic black

women are often due to the lower income and educational

levels of minority women, their limited access to health care

and health insurance, the neighborhoods in which they live,

and other factors (29,30). The causes of these differences merit

intensive investigation, and one purpose of this report is to

discuss some of the factors that explain differences in health

outcomes among white, black, and Hispanic women.

A major finding is that marital status, education, income

level, age at pregnancy outcome, and wantedness of the

pregnancy continue to be important correlates of delayed

prenatal care, health-risking behavior in pregnancy, and low

birthweight. However, the impact of these variables on specific health measures is not uniform among racial and ethnic

groups.

Timing of first prenatal visit

Nearly 98 percent of white and black women with pregnancies ending in a live birth received prenatal care before

delivery. However, black women were less likely to receive

early prenatal care than white women were, and the race gap

in the 1988 NSFG was nearly identical to that observed in the

1982 NSFG (22). Figure 1 shows that 68 percent of white and

54 percent of black women (a difference of 14 percentage

points) received early prenatal care. Among ever-married

women, the difference between the two races was 10 percentage points, but among never-married women, black and white

women were about equally likely to receive early prenatal care

(4 percentage point difference).

For all women, regardless of race or Hispanic origin,

prenatal care was more likely to be delayed beyond the first

trimester if the mother was a teenager, had never married, had

considered her pregnancy unwanted or mistimed at the time of

conception, had never worked, had not finished high school,

had a low income, or had received Medicaid for prenatal care

or delivery costs (an indicator of very low income) (tables

1–6). Although these patterns of associations were fairly

consistent within each race-ethnic group, the proportions

receiving early care were generally lower for Hispanic and

non-Hispanic black women than for non-Hispanic white women.

No significant changes in patterns were found between the

1982 and 1988 NSFG (table A; see figure 2 for an example of

the trend by marital status). This indicates that in 1988 there

was still far to go in reaching the 1990 target level of

90 percent for early prenatal care among all race-ethnic groups.

Source of most prenatal care

White women were more than one and a half times as

likely as black women to receive most of their prenatal care

from a private physician (75 versus 46 percent) versus a

hospital clinic or other clinic (figure 3). The proportions

receiving private physician care increased steadily with income

level for white and black women, but within each income

group, the percent receiving private care was markedly lower

for black women than for white women.

Among both black and white births, prenatal care from a

private physician was less likely if the mother was a teenager,

had never married, had her first visit after the first trimester,

did not want her pregnancy at the time of conception, had

never worked, or had received Medicaid for prenatal care or

delivery costs (tables 7–12).

The question on source of prenatal care changed between

the 1982 and 1988 surveys, preventing a direct examination of

the trend. In 1982 women identified the site of their FIRST

prenatal visit, while in 1988 they identified the site of MOST

of their prenatal visits.

0

10

20

30

40

50

60

70

80

Percent

All women Never married Ever married

Marital status at time of birth

White Black

68

54

45

49

70

60

Figure 1. Percent of mothers receiving prenatal care in the first

trimester, by race of mother and marital status: United States,

1984–88

3
Cigarette smoking during pregnancy

About 27 percent of ever-pregnant women reported smoking during their most recent pregnancy, and black women

were less likely to have smoked than white women (23 versus

29 percent). Figure 4 shows that among less educated women,

pregnancy-related smoking was more common among white

women than black women, but among women who continued

beyond high school, the percents who smoked were equivalent

for black and white women. Another important race difference

was found in smoking according to age—white women smoked

more when younger, particularly under age 20, while black

women smoked more when older, particularly over age 30

(tables 14–15).

Smoking during pregnancy decreased steadily by year of

pregnancy outcome, based on the 1982 and 1988 surveys. Yet

several noteworthy patterns persist. Smoking remains primarily

a practice of women who are under 25 years, have never

married, are less educated, have lower incomes, and have

delayed prenatal care until after the first trimester (tables B

and C). Figure 5 shows how smoking rates have changed over

time, by education level.

Drinking during pregnancy

Nearly 15 percent of ever-pregnant women, regardless of

race, reported drinking once a month or more during their

most recent pregnancy. However, a higher percent of black

women (75 percent) abstained from drinking, as compared

with 63 percent of white women (table 20). Hispanic women

were also more likely to abstain than non-Hispanic white

women.

Figure 6 shows how drinking rates varied by education

level and race. Drinking in pregnancy increased with education among white women, but decreased at higher levels of

education among black women.

Table A. Number of live births to women 15–44 years of age and percent having prenatal visit within first trimester of pregnancy, by

selected characteristics of the birth and mother: United States, 1979–1982 and 1984–1988

Characteristic

1979–1982 1984–1988

Number in

thousands Percent

Number in

thousands Percent

All live births1 ........................ 14,372 67.9 16,220 65.4

Age at birth

Less than 20 years ..................... 1,972 45.7 1,823 39.2

20–24 years ......................... 4,764 61.4 4,562 59.6

25–29 years ......................... 4,863 75.1 5,627 72.9

30–44 years ......................... 2,773 72.1 4,208 73.0

Marital status at time of birth

Never married ........................ 2,471 43.8 2,695 45.9

Ever married ......................... 11,872 70.6 13,526 69.3

Wantedness status at conception

Intended ............................ 9,127 72.6 9,711 71.9

Mistimed ........................... 3,823 56.0 4,487 55.9

Unwanted ........................... 1,422 49.6 1,987 55.1

Race and Hispanic origin

Hispanic ............................ 1,704 65.1 2,115 52.6

Non-Hispanic white ..................... 10,248 71.5 11,025 70.3

Non-Hispanic black ..................... 2,020 55.3 2,287 52.7

Education (at interview)2

Less than 12 years ..................... 2,416 58.0 2,557 49.1

12 years ............................ 4,948 69.2 5,287 66.5

13 years or more ...................... 5,036 79.2 6,554 78.1

Poverty level income (at interview)2

149 percent or less ..................... 3,825 55.8 3,908 52.8

150–299 percent ...................... 4,159 74.9 4,331 67.6

300 percent or more .................... 4,415 80.7 6,158 79.5

Medicaid recipient3

No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12,269 69.2 14,256 67.7

Yes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,059 45.9 1,964 48.7

NOTE: Data for 1979–82 come from Cycle III (1982) of the National Survey of Family Growth (NSFG) in 1982. Data for 1984–88 come from Cycle IV (1988) of the NSFG.

1Includes births with missing data on age at birth or wantedness status. Figures for 1979–82 also include births with missing data on education and income. Includes births to women of other

races, not shown separately.

2Limited to women 20–44 years of age at time of birth.

3In the 1982 National Survey of Family Growth, women were asked explicitly if they were Medicaid recipients. In 1988, women were not asked explicitly, but could report Medicaid payment for

prenatal care or delivery.

4
When women of all races were grouped together, drinking

during pregnancy was associated with numerous measures of

socioeconomic status, including higher education, higher

income, and higher status occupations (table 20). In general,

significant declines in reported drinking during pregnancy

were seen between the 1982 and 1988 NSFG (table D). The

percent of non-Hispanic black women who reported drinking

during pregnancy rose slightly between survey years, but this

was not statistically significant at the 10 percent level.

Low birthweight

The overall rate of low birthweight was 7 percent, with

black singleton births having more than twice (14 percent) the

rate of low birthweight of white singleton births (6 percent).

Among women of all races, low birthweight rates were lower

for mothers who were older, were ever married, wanted their

pregnancies, had more education, had higher-status jobs, or

higher incomes (tables 21–22). While these patterns were

generally similar for white and black births, within each

category black births had consistently higher rates of low

birthweight. The rate of low birthweight for Hispanic women

was similar to that for non-Hispanic white women.

Figure 7 presents the proportions of births that were low

birthweight according to race and amount of smoking during

pregnancy. Both smoking and race were strongly associated

with low birthweight. Smokers had much higher rates of low

birthweight than nonsmokers. In all smoking categories (including ‘‘none’’), the rates of low birthweight were more than

twice as high for black births as for white births. The percent

of low birthweight varied from under 4 percent for white

nonsmokers to over 20 percent for black smokers.

Tables 23 and 24 show that low birthweight rates have

declined markedly over time, from an overall rate of 16 percent for births in 1970 or earlier to an overall rate of 6 percent

for births in 1985–88. Table 23 suggests an apparent widening

of low birthweight rates between smokers and nonsmokers as

overall low birthweight rates have fallen over time. Multivariate adjustment would be required to determine whether this is

a real effect or a result of the changing characteristics of

smokers in the later periods (for example, smokers may be less

educated, younger, unmarried). Table 24 illustrates the persistent black-white race gap in low birthweight over time.

Although the rate fell from 32 percent among black births in

1970 or earlier to 12 percent among black births in 1985–88,

black low birthweight rates remain over twice those seen

among white births.

Source of payment for delivery

There were dramatic differences in how deliveries were

paid for, according to demographic and socioeconomic char0

20

40

60

80

Percent

All marital

statuses

Never married Ever married

Marital status at time of birth

66

44

71

1979 82

65

46

69

1984 88

Figure 2. Percent of mothers receiving prenatal care in the first

trimester, by marital status of mother and year of birth of child:

United States

0

20

40

60

80

100

Percent

All women Less than

150

percent

150 299 More than

Poverty level income

75

54

79

84

White

46

38

50

64

Black

percent 300 percent

Figure 3. Percent of mothers receiving prenatal care for a birth in

1984–88 and who received most prenatal care from a private

physician, by race and poverty level income: United States

0

10

20

30

40

50

Percent

All

education

levels

Less than

12 years

12 years More than

12 years

Education

29

46

31

19

23

35

19 19

White Black

Figure 4. Percent of women who reported any amount of

cigarette smoking during their most recent pregnancy, by race

and education: United States, 1988

5
acteristics of the mother. The strongest correlates of private

insurance payment for delivery costs were being ever-married,

older, and white (tables 25–30). Insurance payment was also

more prevalent among women who had higher levels of

education, higher-status jobs (or any job at all), or higher

income.

Figure 8 illustrates how payment for deliveries between

1984 and 1988 varied by race. Only 40 percent of black births

were paid for, partly or totally, by private insurance, compared

with 71 percent of white births. (Note that these forms of

payment are not mutually exclusive categories.) Black births

were nearly 5 times as likely to be paid for by Medicaid as

white births (33 versus 7 percent).

Figure 9 shows the percent distribution (mutually exclusive categories summing to 100 percent) of most recent live

births (occurring in 1984–88) by source of payment and

marital status. Insurance, alone or in conjunction with out-ofpocket funds, covered 76 percent of deliveries for evermarried women, while covering only 25 percent of deliveries

for never-married women. Among never-married women, the

predominant sources of payment were Medicaid (34 percent)

and other government programs (23 percent) (table 31).

Figure 10 depicts the percent of deliveries paid for by

Medicaid in 1979–82 and in 1984–88, by age of the mother.

None of the changes in payment by Medicaid or private

insurance, or by maternal and birth characteristics, were

significant between the two survey years (table E). Medicaid

continued to be a major source of payment for delivery among

teenagers, but not among women 25 and older.

Table B. Number of women 15–44 years of age whose most recent pregnancy ended in a live birth or spontaneous loss and percent who

reported any amount of cigarette smoking during pregnancy, by year pregnancy ended and selected characteristics of the pregnancy

and mother: United States

Characteristic

1982 NSFG1 1988 NSFG

1970 or earlier 1971–1980 1981–1984 1985–1988

Number in

thousands

Percent

smoked

Number in

thousands

Percent

smoked

Number in

thousands

Percent

smoked

Number in

thousands

Percent

smoked

All women2 ................... 6,673 34.7 18,197 32.0 7,960 25.9 11,661 23.4

Age at pregnancy outcome

Less than 20 years . . . . . . . . . . . . . . 717 33.9 1,908 44.7 545 41.8 1,081 28.1

20–24 years .................. 2,840 37.2 5,292 35.0 1,813 32.0 3,009 30.2

25–29 years .................. 2,490 33.0 6,688 28.1 2,752 26.2 4,036 23.6

30–44 years . . . . . . . . . . . . . . . . . . 600 30.4 4,194 28.6 2,805 18.5 3,501 15.8

Marital status at pregnancy outcome

Never married . . . . . . . . . . . . . . . . . 323 40.2 2,296 43.0 991 38.1 2,066 32.0

Ever married .................. 6,219 33.7 15,715 30.4 6,925 24.1 9,560 21.5

Pregnancy outcome

Live birth .................... 6,243 34.5 16,105 30.3 7,165 25.3 9,981 22.7

Spontaneous loss . . . . . . . . . . . . . . . 407 36.6 1,978 45.7 752 31.1 1,645 27.6

Wantedness status at conception

Intended ..................... 3,874 33.2 11,080 29.4 4,734 20.8 6,857 19.1

Mistimed .................... 1,638 31.6 4,209 36.0 1,825 32.3 3,120 27.5

Unwanted .................... 1,108 43.3 2,712 36.5 1,352 35.4 1,624 33.1

Race and Hispanic origin

Hispanic . . . . . . . . . . . . . . . . . . . . . 384 29.6 1,752 20.9 850 16.6 1,571 13.1

Non-Hispanic white .............. 5,267 36.4 13,129 33.8 5,696 27.4 7,856 26.7

Non-Hispanic black . . . . . . . . . . . . . . 874 29.6 2,659 31.5 1,104 26.4 1,634 19.9

Education (at interview)3

Less than 12 years .............. 1,290 45.8 3,168 46.6 1,267 47.3 1,866 38.3

12 years ..................... 2,787 35.1 6,763 33.9 2,744 27.1 3,717 26.6

13 years or more ............... 1,854 26.6 6,243 18.6 3,361 14.2 4,962 14.3

Poverty level income (at interview)3

149 percent or less .............. 1,043 32.8 3,905 39.2 1,801 38.9 2,799 32.3

150–299 percent ............... 1,848 35.9 5,424 30.5 2,145 25.3 2,983 23.1

300 percent or more ............. 3,039 34.7 6,845 25.5 3,425 16.9 4,764 17.2

NOTE: Data exclude current pregnancies and pregnancies ending in induced abortion because smoking during pregnancy was not asked.

1NSFG is National Survey of Family Growth.

2Totals based on 1982 National Survey of Family Growth include women with missing data on age at outcome, birthweight, wantedness status, education, or income; totals based on 1988 NSFG

include women with missing data on wantedness status. Total also includes women of other races, not shown separately.

3Limited to women 20–44 years of age at time of pregnancy outcome.

6
Table C. Number of women 15–44 years of age whose most recent pregnancy ended in a live birth or spontaneous loss and percent

distribution by whether they smoked cigarettes or drank alcohol during pregnancy, according to selected characteristics of the

pregnancy and mother: United States, 1988

Characteristic

Number in

thousands

Smoking and drinking during most recent pregnancy1

Total

Neither

smoked nor

drank Subtotal

Smoked

only

Drank

only

Both smoked

and drank

Percent distribution

All women2 ..................... 32,465 100.0 51.1 48.9 15.4 21.3 12.1

Age at pregnancy outcome

Less than 20 years ................ 2,966 100.0 57.6 42.4 20.5 10.2 11.7

20–24 years .................... 9,718 100.0 49.6 50.4 18.4 17.0 15.0

25–29 years .................... 11,657 100.0 49.7 50.3 14.8 23.0 12.5

30–44 years .................... 8,123 100.0 52.7 47.3 10.8 28.2 8.3

Marital status at pregnancy outcome

Never married ................... 4,468 100.0 52.5 47.5 19.1 13.8 14.6

Ever married .................... 27,997 100.0 50.9 49.1 14.8 22.5 11.7

Wantedness status at conception

Intended ....................... 19,437 100.0 53.4 46.6 13.5 22.2 10.8

Mistimed ...................... 8,011 100.0 48.1 51.9 17.0 20.9 14.0

Unwanted ...................... 4,960 100.0 47.4 52.6 20.3 18.3 14.1

Year of pregnancy outcome

1985–1988 ..................... 11,661 100.0 55.2 44.8 14.1 21.4 9.3

1981–1984 ..................... 7,960 100.0 52.2 47.8 15.6 21.9 10.4

1980 or earlier ................... 12,844 100.0 46.8 53.2 16.5 20.9 15.8

Race and Hispanic origin

Hispanic ....................... 3,402 100.0 68.6 31.4 7.0 17.7 6.7

Non-Hispanic white ................ 23,419 100.0 45.9 54.1 17.5 23.6 13.0

Non-Hispanic black ................ 4,545 100.0 62.6 37.4 12.1 13.9 11.4

Non-Hispanic other ................ 1,098 100.0 62.1 37.9 11.3 14.2 12.4

Education (at interview)3

Less than 12 years ................ 5,203 100.0 46.0 54.0 28.0 10.9 15.1

12 years ....................... 11,612 100.0 52.2 47.8 16.1 18.8 13.0

13 years or more ................. 12,547 100.0 50.8 49.2 8.3 30.7 10.2

1Data exclude current pregnancies and pregnancies ending in induced abortion because smoking and drinking during pregnancy were not asked.

2Includes women with missing data on smoking and drinking during pregnancy or wantedness status.

3Limited to women 20–44 years of age at time of pregnancy outcome.

0

10

20

30

40

50

Percent

Less than 12

years

12 years More than

12 years

Education

46

35

27

1970 or earlier

47

34

19

1971 80

47

27

14

1981 84

38

27

14

1985 88

Figure 5. Percent of ever-pregnant women who smoked during

their most recent pregnancy, by education and year of

pregnancy outcome: United States

0

5

10

15

20

25

Percent

All

education

levels

Less than

12 years

12 years More than

12 years

Education

15

11

12

20

14

19

14

11

White Black

Figure 6. Percent of ever-pregnant women who drank once a

month or more during their most recent pregnancy, by race and

education: United States, 1988

7
Table D. Number of women 15–44 years of age whose most recent pregnancy ended in a live birth or spontaneous loss and percent

who reported drinking at all during pregnancy, by selected characteristics of the pregnancy and mother: United States, 1982 and 1988

Characteristic

1982 NSFG1 1988 NSFG

Number in

thousands

Percent

who drank

Number in

thousands

Percent

who drank

All women2 ..................... 32,465 45.4 32,465 33.5

Age at pregnancy outcome

Less than 20 years ................ 3,609 31.2 2,966 22.1

20–24 years .................... 10,615 40.5 9,718 32.0

25–29 years .................... 11,814 52.3 11,657 35.4

30–44 years .................... 6,424 48.6 8,123 36.6

Marital status at pregnancy outcome

Never married ................... 3,895 37.5 4,468 28.4

Ever married .................... 28,353 46.5 27,997 34.3

Race and Hispanic origin

Hispanic ....................... 3,017 30.5 3,402 24.4

Non-Hispanic white ................ 23,859 50.1 23,419 36.7

Non-Hispanic black ................ 4,626 17.0 4,545 25.3

Education (at interview)3

Less than 12 years ................ 5,660 33.3 5,212 25.9

12 years ....................... 12,274 46.4 11,624 31.8

13 years or more ................. 10,919 55.1 12,560 40.8

Poverty level income (at interview)3

149 percent or less ................ 6,938 35.1 6,655 27.5

150–299 percent ................. 9,404 46.2 8,164 30.5

300 percent or more ............... 12,512 54.5 14,577 40.2

NOTE: Data exclude current pregnancies and pregnancies ending in induced abortion because drinking during pregnancy was not asked.

1NSFG is National Survey of Family Growth.

2Includes women with missing data on age at pregnancy outcome, marital status at outcome, race and ethnicity, education, or income. Includes women of other races, not shown separately.

3Limited to women 20–44 years of age at time of pregnancy outcome.

0

5

10

15

20

25

Percent

All births None Less

than 15

15 or more

Number of cigarettes smoked per day during pregnancy

6.1

3.6

8.1

9.0

14.2

10.6

22.4

20.5

White Black

Figure 7. Percent of most recent single live births to women

15–44 years of age that were low birthweight, by race and

number of cigarettes smoked per day during pregnancy: United

States, 1988

20

40

60

80

Percent

Own

income

Insurance Medicaid Other

government

Other

sources

Source of payment for delivery

47

71

7 8

3

27

40

33

16

3

0

White Black

Figure 8. Percent of live births in 1984–88 that were paid for, in

whole or part, from specified sources, by race of mother: United

States

8
0

10

20

30

40

50

Percent

Own

income

only

Insur

ance

only

Own

income

and

insurance

Medicaid

only

Other

govern

ment

only

All

other

combin

ations

Source of payment of delivery

11

17

8

34

23

7

11

41

35

4 5 4

Never married Ever married

Figure 9. Percent distribution of most recent live births (1984–88)

by source of payment for delivery and marital status: United

States

0

5

10

15

20

25

30

35

Percent

All ages Less

than 20

years

25 29 30 44

Age of mother at time of delivery

10

27

13

5 4

1979 82

11

30

15

7

4

20 24

years years years

1984 88

Figure 10. Percent of deliveries paid in whole or in part by

Medicaid, by age of mother and year of birth: United States

Table E. Number of live birth deliveries to women 15–44 years of age and percent paid by private insurance or Medicaid, by selected

characteristics of the birth and mother: United States, 1979–82 and 1984–88

Characteristic

1979–1982 1984–88

Number in

thousands

Private

insurance Medicaid

Number in

thousands

Private

insurance Medicaid

All live births1 ................... 14,372 62.4 10.3 16,220 65.7 11.0

Age at birth

Under 20 years .................. 1,972 27.1 26.7 1,823 30.1 29.9

20–24 years .................... 4,764 55.6 13.4 4,562 53.0 15.4

25–29 years .................... 4,863 74.2 4.6 5,627 75.4 6.8

30–44 years .................... 2,773 78.5 3.5 4,208 82.2 3.7

Marital status at time of birth

Never married ................... 2,471 18.1 39.2 2,695 23.0 38.0

Ever married .................... 11,872 71.6 4.3 13,526 74.2 5.7

Race and Hispanic origin

Hispanic ....................... 1,704 41.8 19.6 2,115 41.4 20.6

Non-Hispanic white ................ 10,248 70.8 5.0 11,025 75.2 5.0

Non-Hispanic black ................ 2,020 36.8 30.1 2,287 39.9 32.6

NOTE: Data for 1979–82 are from Cycle III (1982) of the National Survey of Family Growth (NSFG). Data for 1984–88 are from Cycle IV (1988) of the NSFG.

1Includes deliveries with missing data on payment, age at birth, marital status at birth, or race and ethnicity. Totals also include births to women of other races, not shown separately.

9
Source and limitations

of the data

Cycle IV (1988) of the National Survey of Family Growth

(NSFG) was based on personal interviews with a multistage

area probability sample of 8,450 women 15–44 years of age in

the civilian noninstitutionalized population of the United

States. In 1988, women from Alaska and Hawaii were included

for the first time in the NSFG. Cycle III in 1982 was the first

cycle in which women were interviewed regardless of marital

status. The 8,450 women interviewed for the 1988 NSFG were

located from households in which someone had already been

interviewed for another NCHS survey, the National Health

Interview Survey (NHIS), between October 1985 and March

1987. Black women were sampled at higher rates than other

women to increase the reliability of statistics for this group.

Between January and August of 1988, trained female

interviewers conducted in-person interviews with 5,354 white

women, 2,771 black women, and 325 women of other races.

The interview, which lasted an average of 70 minutes, focused

on the woman’s pregnancies, if any; her use of contraception;

her ability to bear children (fecundity and infertility); her use

of medical services for family planning, infertility, and prenatal care; her marriage and cohabitation history, if any; and a

wide range of demographic and economic characteristics.

Characteristics such as race, Hispanic origin, parity, education, and geographic region refer to the woman at the time

she was interviewed. Terms such as ‘‘black births’’ refer to

births to black women, regardless of the race of the father.

Similarly, women living in families with incomes below

150 percent of poverty level are referred to as ‘‘low-income’’

women, and women living in families with incomes of greater

than or equal to 300 percent of poverty level are referred to as

‘‘high-income’’ women.

The statistics cited are estimates for the national population from which the sample was drawn. Because the estimates

are based on a sample, they are subject to sampling variability.

The estimates may be affected by nonsampling errors that may

have been introduced during interviewing, data processing,

and analysis, although stringent quality control measures were

used at each stage to minimize errors as much as possible.

Further discussion of the NSFG survey design and sampling

variability is in the appendixes, as well as in a detailed report

(31) on design, estimation, and inference in the 1988 survey.

In this report, the term ‘‘similar’’ means that any observed

difference between two estimates being compared is not

statistically significant at the 10-percent level. Terms such as

‘‘greater,’’ ‘‘less,’’ ‘‘larger,’’ ‘‘smaller,’’ ‘‘more likely,’’ and

‘‘less likely’’ indicate that the observed differences are statistically significant at the 5-percent level using a two-tailed

z-test (normal deviate test). Statements that are qualified in

some way (for example, ‘‘the data suggest’’) indicate that the

observed difference is significant at the 10-percent level, but

not at the 5-percent level.

The following sections in this report include comparisons

with other data and detailed descriptions of survey findings on

timing of first prenatal care visit, source of most prenatal care,

smoking and alcohol use during pregnancy, low birthweight,

and sources of payment for delivery of live births. Appendix I

contains technical notes on how the NSFG was designed and

conducted, appendix II consists of definitions of the variables

used in this report, and appendix III includes the survey

questions on the topics covered in this report.

Although the 1982 and 1988 NSFG Cycles offer a wide

range of explanatory variables that can clarify the health

aspects of pregnancy and childbirth in the United States, there

are many factors that could not be included because of limits

on the length and cost of the interview. For example, basic

sociodemographic and employment information about women’s current husbands or cohabiting partners were collected,

but such information about the father of pregnancies described

in this report may not be included. A woman’s relationship

with her baby’s father has been associated with the receipt of

timely and adequate prenatal care (32), and other paternal

characteristics such as education, race, and smoking (that is,

passive exposure to maternal or paternal cigarette smoke) have

been linked to rates of low birthweight, sudden infant death

syndrome, and preterm delivery (33–35). Furthermore, it is

recognized that there are complex relationships among many

of the variables used in these tabulations. Multivariate analyses of these data would be worthwhile, but they are beyond the

scope of this report.

10
Comparisons with other data

The data in this report are from the 1988 National Survey

of Family Growth. Comparisons of NSFG pregnancy and

childbirth data can be made with vital registration data. In

addition to basic sociodemographic characteristics of the

baby’s parents, the U.S. Standard Certificate of Live Birth

includes information on birthweight, timing of initial prenatal

visit, and number of prenatal visits. Beginning in 1983, the

National Center for Health Statistics has produced the annual

Linked Birth and Infant Death Files that permit analyses of

infant mortality and low birthweight using the data from birth

and death certificates. The latest available file is for the 1988

birth cohort (36).

The 1989 revision of the birth certificate added several

new items, including smoking and drinking during pregnancy

and pregnancy-related morbidity, which will be useful in

monitoring risk factors for difficult pregnancies and poor

pregnancy outcomes (37,38). Meanwhile, the 1988 and earlier

NSFG Cycles remain one of the few sources of reliable

national trend data on the source of prenatal care, the sources

of payment for prenatal care and delivery, and smoking and

alcohol use in pregnancy.

Other sources

In recent years, several national and State-level surveys

have emerged that offer data comparable to the NSFG on

pregnancy and childbirth. The 1988 National Maternal and

Infant Health Survey (NMIHS) contains information on women

who had 9,953 live births, 5,332 infant deaths, and 3,309 fetal

deaths. Data were collected from the women themselves, the

hospitals where births and infant deaths occurred, and the

medical providers of prenatal care (39). The NMIHS is more

clinically oriented than the NSFG and focuses primarily on the

specific pregnancy and birth sampled. In contrast, the NSFG is

primarily a demographic survey and includes data on the

entire fertility history of individual women.

A recently begun initiative in monitoring health aspects of

pregnancy and childbirth is the Pregnancy Risk Assessment

Monitoring System (PRAMS), an ongoing, population-based

surveillance system designed to supplement vital records data

and to generate State-specific data for planning and evaluating

maternal and child health programs (40). Using selfadministered questionnaires, partly tailored to individual States,

PRAMS collects information similar to the NSFG on prenatal

care, birthweight, smoking and drinking in pregnancy, and

socioeconomic characteristics. In 1987, PRAMS was operational in five States plus the District of Columbia; as of early

1993, PRAMS is under way in 22 States plus the District of

Columbia.

Low birthweight

Data on birthweight are published each year from the U.S.

birth registration system, by such characteristics as race, age,

marital status, and education of the mother; birth order; and

month of the pregnancy in which prenatal care began. It is

important to recognize that birth registration data are based on

complete counts of all births and refer only to births in a

particular calendar year. The NSFG data used for this report

are based on a sample of births that occurred over several

calendar years up to 1988. In addition, the tabulations of low

birthweight—2,500 grams (5 pounds 8 ounces) or less—in this

report are limited to single live births because twins, triplets,

and other multiple births are more likely to be low birthweight

than single births. One purpose of this report is to present

birthweight data that may further clarify the observed racial

and ethnic group disparities. Another distinction between the

NSFG data and birth registration data is that the NSFG sample

size is not large enough to study births with very low

birthweight (less than 1,500 grams).

The following table shows a sample comparison of the

1988 NSFG with 1985 and 1988 data on registered births

(41,42), the percent of single live births that were low

birthweight, by race:

Race

NSFG

(± 2 standard errors)

Registered births

1985 1988

All races ............. 7.4(± 0.8) 6.7 6.9

White .............. 6.1(± 0.4) 5.6 5.6

Black ............... 14.2(± 2.4) 12.4 13.0

The numbers in parentheses after the NSFG figures show

two standard errors around the NSFG estimate of the lowbirthweight rate. (The standard errors for registered birth data

are essentially zero when rounded to one decimal place.) In

each case, though they are consistently higher, the NSFG

estimates do not differ significantly from the birth registration

data; that is, the registered birth figures fall within the range of

two standard errors. Thus, the NSFG estimates of low birthweight based on mother’s reports, often several years after the

birth, are comparable to those in the birth registration system,

which are obtained primarily from hospitals at the time of

delivery.

11
Timing of first prenatal visit

In the 1988 NSFG, women who had a live birth between

1984 and 1988 were asked: ‘‘During this pregnancy, did you

ever visit a doctor or clinic for prenatal care?’’ If the mother

responded ‘‘yes,’’ she was asked: ‘‘How many months pregnant were you when you first visited a doctor or clinic for

prenatal care?’’

Prenatal care was defined for the respondent as not

including visits simply for pregnancy tests; that is, she was not

to count a visit during which she only learned she was

pregnant as prenatal care. On the U.S. birth certificate, the

mother or the doctor provides information about the ‘‘month

of pregnancy prenatal care began’’ (first, second, etc.). In the

1988 NMIHS, women were asked: ‘‘How many weeks pregnant were you when you went for your first prenatal visit?’’

Prenatal care was defined as including visits that may have

only consisted of pregnancy tests. Information was obtained

by maternal self-report as well as provider reports.

Differences in the wording of these questions among the

data sources, as well as differences in methods of data

collection, time reference of the questions, definitions of

prenatal care, and sampling error, account for much of the

variation among the data sources with respect to timing of

initial prenatal visit. In general, a smaller proportion of women

in the 1988 NSFG than in the vital registration data or the

1988 NMIHS reported beginning care in the first trimester.

Vital records indicate that the overall proportion receiving

early care has been stable at 76 percent since 1979, and the

proportion receiving no care or beginning care in the third

trimester has remained at 6 percent since 1983 (41).

The disparity in timing of first prenatal care was more

striking between the NSFG and the NMIHS, probably due to

the different definitions of prenatal care. The NSFG estimates

that about 65 percent of births in 1984–88 received prenatal

care in the first trimester (table 1). The NMIHS showed that

over 80 percent of pregnant women in their 1988 sample

began care in the first trimester (43). The NSFG white-black

differential was 68 percent versus 54 percent (figure 1), compared with 85 percent versus 64 percent in the NMIHS (43).

The higher levels of early care seen in the NMIHS may be due

to that survey’s inclusion of pregnancy tests in its definition of

prenatal care.

These differences are important because they give different impressions of the progress that has been made toward the

national public health goal of having at least 90 percent of all

subgroups of pregnant women receive prenatal care within the

first trimester. Many researchers have stressed the importance

of further methodologic research and standardization of measurement (44–46). For example, cognitive work on how best

to ask questions on prenatal care would be worthwhile because

‘‘prenatal care’’ may be a complex concept or a technical term

that women interpret differently. It should be noted that despite

the significant variations in estimates of early prenatal care,

the patterns of associations with pregnancy and maternal

characteristics are remarkably similar across all data sources.

This lends greater confidence in the NSFG findings, particularly for those variables not contained in vital records or other

survey data.

Other pregnancy-related variables

The NSFG and NMIHS data yield comparable findings

for the source of most prenatal care and payment for prenatal

care and delivery. For example, in the NMIHS, about 70 percent of pregnant women received most of their care from

private providers, the same percent seen with NSFG data

(table 7). The percents receiving private care by race were also

similar between the surveys. Similar proportions in both

surveys reported paying for prenatal care and delivery with

private insurance and with Medicaid.

Both surveys contained questions about smoking and

drinking in pregnancy, but they were asked in somewhat

different ways. The NMIHS asked women if they smoked or

drank in the year before delivery, a recall period that includes

months during which they were not pregnant. As a result, the

NMIHS figures may overestimate the prevalence of these

behaviors during the pregnancy.

The NSFG asked women if they smoked or drank during

their most recently completed pregnancy (if ending in spontaneous loss or live birth), a wording that may have resulted in

an underestimate of smoking and drinking among women who

did not learn they were pregnant until well into the pregnancy.

Despite this difference, the NMIHS figure for smoking was

32 percent, quite close to the NSFG figure of 27 percent

(table 13). The NMIHS figure for drinking was 50 percent,

versus 33 percent in the NSFG (table 19), probably because

the NMIHS referred to a 12-month period that predated the

start of the pregnancy, while the NSFG only asked about

drinking during the pregnancy.

12
Findings

Timing of first prenatal visit

Early, regular, and appropriate prenatal care has been

linked to reduced rates of pregnancy complications, of preterm

delivery, of low birthweight, and of perinatal illness or death

(13,20,47). The benefits gained in maternal and infant health

are particularly striking for women at higher risk for poor

outcomes (8,20,48–50). In addition to health benefits, studies

have illustrated considerable potential for health care cost

savings. For example, in a cost-benefit analysis of prenatal

care among Medicaid recipients in Missouri, a savings of

$1.49 in newborn and postpartum costs was found to result

from each extra $1 spent on prenatal care (51).

Despite considerable debate about how best to evaluate

prenatal care (for example, the impact of specific styles or

components of prenatal care) (8,20,44,46), there is general

consensus in the literature that quality prenatal care programs

are vital for providing necessary medical care and advice that

will prevent serious complications for both mother and baby.

In addition, prenatal care programs have the potential to

improve the general health status of some pregnant women,

for whom prenatal care may be the only source of medical

attention. Early and comprehensive prenatal care thus offers a

woman several critical benefits (8,13):

+ Counseling on stopping the use of cigarettes, alcohol, and

other drugs; on nutrition; and on other lifestyle factors that

affect her and her baby’s health.

+ Identifying and managing maternal medical conditions

such as diabetes and high blood pressure.

+ Assessing risk for problems such as preterm delivery, low

birthweight, premature rupture of membranes, and other

pregnancy complications.

Although the importance of content and timing of subsequent visits is well recognized (44,52–54), the timing of the

initial prenatal visit is widely used as a convenient indicator of

the adequacy of care. Increasing to at least 90 percent the

proportion of all pregnant women who begin prenatal care

within the first trimester is an objective of the national

‘‘Healthy People 2000’’ initiative (55). Tables 1–6 present

1988 NSFG data on prenatal care initiation among American

women in the mid 1980’s (1984–88). These tables show that

all groups of pregnant women fell short of this national health

goal. The tables also show the wide disparities that exist

according to race, Hispanic origin, marital status, age, and

other factors in the rate at which groups are achieving the

goal.

Some women, for a variety of reasons, may not recognize

that they are pregnant while they are in their first trimester.

Often, these are women at higher risk of adverse pregnancy

outcomes, and they may only learn of their pregnancy when

they miscarry or have other difficulties. Other women may

experience pregnancy loss within the first trimester and never

have the opportunity to receive prenatal care. To circumvent

these and other limitations, the 1988 NSFG restricted its

prenatal care questions to women whose pregnancies ended in

live birth between January 1984 and the interview in 1988.

Characteristics of the birth

Table 1 shows that the timing of the initial prenatal visit

varied according to selected characteristics of the birth for all

women regardless of race. Younger women, particularly those

under age 25 years at delivery, were much less likely to begin

prenatal care within the first trimester. Only 39 percent of

teenaged mothers and 60 percent of mothers 20–24 years

began prenatal care in the first 3 months, compared with

73 percent of mothers 25–44 years old. As seen with births

occurring in 1979–82 (22), teenaged mothers were three times

as likely as mothers 25–29 years old to delay prenatal care

beyond 5 months or to receive no care at all. Many reports

have documented this association in birth registration data

(37,41), as well as in survey data in which confounding

variables were controlled by multivariate analysis (18,56).

First and second order births were more likely than third or

higher-order births to receive early prenatal care, a finding

consistent with reports based on vital statistics and survey data

(18,41,42). No difference was found in timing of first prenatal

care by mode of delivery.

Only 46 percent of never-married women received early

prenatal care, far less than the 70 percent of ever-married

women. Many studies have found similar disparities by marital status, largely attributable to the fact that single mothers are

disproportionately younger, less educated, and have lower

incomes than married mothers (8,20,56). About 72 percent of

pregnancies that were intended at the time of conception

received early prenatal care, compared with approximately

55 percent of mistimed or unwanted pregnancies. These findings are consistent with 1980 National Natality Survey results.

13
Those data showed that among births to married white women,

planning status of pregnancy (a measure of wantedness) was

associated with timing of first prenatal care (57).

Tables 2 and 3 reveal large black-white differences in the

timing of first prenatal care. About 68 percent of white births

received care within the first trimester, versus 54 percent of

black births. The black-white difference in receiving first

trimester care is relatively small for teenagers and women

20–24 years old, but increases to a 16-point difference (60

versus 76 percent) for women aged 30–44 years. A similar

pattern of prenatal care timing is seen by birth order among

black and white births, but the rates of early care are consistently lower among black births than among white births. As

when all births were examined together, mode of delivery and

birthweight were not related to prenatal care initiation for

black or white births.

Less than 50 percent of never-married women, black or

white, received early prenatal care (figure 1). Among evermarried women, white mothers were more likely to receive

first trimester care than black women were, but the difference

for ever-married women was largely made up in the third and

fourth months of pregnancy, suggesting that delayed recognition of pregnancy may be responsible for some of the delay in

prenatal care. The pattern by wantedness status suggested that

intended (or ‘‘wanted then’’) births, regardless of mother’s

race, were more likely to receive first trimester care.

Characteristics of the mother

The timing of first prenatal care for all live births in

1984–88, according to selected maternal characteristics determined at the time of interview, is shown in table 4. (Note that

for all tables presenting maternal characteristics in this report,

some characteristics (other than race) may have changed

between the child’s birth and the date of interview.) About

53 percent of Hispanic women and non-Hispanic black women

began prenatal care in the first trimester, significantly less than

the 70 percent of non-Hispanic white women who began care

early. Among women who delayed care beyond 5 months or

received no care at all, the gap between Hispanic and nonHispanic white women narrowed from 17 to 12 percentage

points, while the gap between non-Hispanic black and white

women was narrowed more significantly from 17 to 8 percentage points.

Prenatal care in the first trimester (that is, early care) was

markedly associated with several measures of socioeconomic

status. Women with higher levels of education, professional or

managerial jobs, and higher levels of income were more likely

to receive early prenatal care. (Note that for education,

occupation, and income, these and subsequent tables show

data only for women 20–44 years old at time of birth.

Teenagers are likely to still be in high school. They are also

more likely to be unemployed or have lower status jobs, and to

have low incomes or not know their total family income.)

Relative to women who had never worked, women in all

occupational groups showed significantly higher proportions

with early prenatal care (table 4). Only 49 percent of women

who received Medicaid payments for prenatal care or delivery

received early care, versus 68 percent among non-Medicaid

recipients (table 4). Women who lived in suburban areas were

more likely to have early care than women in central cities of

metropolitan areas or nonmetropolitan areas.

Tables 5 and 6 present variations by race in prenatal care

timing according to these same maternal characteristics. The

proportions receiving early care were similar for white and

black women with less than a high school education or with

any amount of college. However, white high school graduates

were about 30 percent more likely to receive early care than

black high school graduates (68 versus 53 percent). In every

job category, white women were more likely to get early care

than black women, but differences were only statistically

significant for those in higher status jobs. About 61 percent of

births to nonmetropolitan white women and only 44 percent of

births to nonmetropolitan black women received early care.

Although early prenatal care rates were similar among

low income women and among Medicaid recipients, white

nonrecipients of Medicaid were almost 25 percent more likely

than black nonrecipients of Medicaid to begin prenatal care in

the first 3 months of pregnancy. However, it should be noted

that the women who did not receive Medicaid are a large and

extremely heterogeneous group with regard to socioeconomic

status.

Trends: Cycles III–IV

Table A gives the proportion of live births receiving

prenatal care within the first trimester, according to selected

birth and maternal characteristics and survey year. Figure 2

shows the percent of mothers receiving early prenatal care in

1979–82 versus 1984–88, by marital status. None of the

changes in rates of early care shown in table A or figure 2

were significant between the 1982 and 1988 surveys. This

suggests that little progress was made toward the 1990 target

level of 90 percent in the early and mid 1980’s. However,

effort toward achieving this target level has continued in the

Healthy People 2000 objectives (55).

Summary

Similar levels and patterns of early prenatal care were

found between the 1982 and 1988 surveys. The likelihood of

receiving delayed care (that is, after the first trimester) remains

significantly higher for the following groups of women:

+ never married

+ teenaged

+ Hispanic and non-Hispanic black

+ having unwanted or mistimed birth

+ never worked

+ low income (less than 150 percent of poverty level)

+ Medicaid recipient

+ education less than high school

The percent receiving early care among all mothers taken

together (65 percent) still falls far short of the 90 percent

objective specified in the nation’s 1990 and Healthy People

2000 programs. This, along with the wide disparities among

14
subgroups of mothers, indicates that further efforts are needed

to extend early prenatal care to all pregnant women.

Source of most prenatal care

Although many studies of prenatal care have been published in recent years, few have presented findings on the

source of care for pregnant women, and almost none are based

on nationally representative samples of women. In 1982 and

1988, the NSFG asked women to identify their source of

prenatal care. Unfortunately, trends over time cannot be examined because the question changed. In 1982, women were

asked where they had their FIRST prenatal visit, but in 1988

they were asked the site of MOST of their prenatal visits. To

the extent that these measures are comparable (that is, the

extent to which women stay with the same provider throughout their pregnancy), the 1982 and 1988 NSFG data indicate

that some important changes occurred in the proportion of care

that was from private physicians.

As for other data sources, birth registration data include

timing of first prenatal care, but do not contain information on

providers. Compared with the NSFG, the National Maternal

and Infant Health Survey (NMIHS) data on timing and source

of prenatal care have suggested similar patterns, if not levels,

of early prenatal care and care provided by private physicians

(43). Pregnancy Risk Assessment Monitoring System (PRAMS)

data from four States in 1988–89 indicated associations between

maternal sociodemographic characteristics and source of prenatal care that were similar to those revealed in national

estimates from the 1988 NSFG (58,59). Women with higher

incomes, better education, and higher-status jobs were more

likely to have private medical insurance to cover their prenatal

care. Insurance status was also found to be the key determinant of source of prenatal care in a North Carolina-based study

in which uninsured women and Medicaid recipients relied

primarily on public clinics (60).

Private physician care is generally associated with better

pregnancy outcomes, but this is largely due to the fact that

women who use private doctors are often in better health

before their pregnancy begins (8). However, the literature does

not firmly indicate that low-income women, generally with

higher risk profiles, do better with private physician care than

they would with clinic (public-sector) care. Many researchers

have suggested that low-income women receiving prenatal

care from public health department clinics and other

government-subsidized facilities show better pregnancy outcomes than low-income women receiving care from private

physicians. Therefore, they have argued for expanding public

clinics and Medicaid eligibility to cover more women in

poverty (60–63). Researchers have also argued for boosting

(or to refrain from further restricting) comprehensive prenatal

services in public health care facilities because many of the

barriers to early and adequate prenatal care are related to clinic

features such as long waiting times, less continuity of care,

and difficult transportation and child care arrangements

(8,20,44,59). Despite the increased numbers of counties offering routine maternity and related services between 1975 and

1984, 40 percent of U.S. counties did not offer prenatal care in

health department operated or funded sites in 1984 (63).

Tables 7–12 present NSFG data on source of prenatal care

for women whose live births occurred between 1984 and

1988. These tables also show the near-universal proportions of

women who received any prenatal care at all.

Receipt of prenatal care

Less than 2 percent of women who had live births between

1984 and 1988 went without any prenatal care, regardless of

race or any of the birth and maternal characteristics shown in

tables 7–12. None of the differences in use of any prenatal care

was significant at the 5 percent level. Furthermore, these rates

represent no substantial change from the rates of prenatal care

receipt among pregnancies ending in live birth between 1979

and 1982, as measured in the 1982 NSFG.

Characteristics of the birth

Table 7 indicates that 69 percent of all births receiving

prenatal care had most of their visits with a private physician,

while the remainder were primarily cared for at hospital

clinics or other clinics. The proportions managed primarily by

private physicians increased markedly with maternal age, from

42 percent among teenaged births, to over 75 percent after age

25 years. The data suggest that babies born by cesarean

section were more likely than babies born vaginally to have

received private care. This is consistent with reports that

women with private health insurance have higher rates of

cesarean delivery than women who use other means to pay for

their deliveries (64).

Marital status, wantedness status, and timing of first

prenatal visit were all closely linked with source of most

prenatal care. Private physician care was more likely among

women who were ever-married (74 percent versus 46 percent),

who had intended pregnancies rather than mistimed or unwanted

pregnancies (74 percent versus 64 percent and 58 percent),

and who had their first prenatal visit within the first trimester

(73 percent versus 58 percent).

‘‘Hospital clinics’’ and ‘‘other clinics’’ include public

health department clinics and other government subsidized

facilities. Greater use of these clinics for prenatal care was

seen among teenaged mothers and women who were having

nonsecond order births, had never married, were having

unintended pregnancies, or who delayed prenatal care beyond

the first trimester.

Tables 8 and 9 present race-specific data on the source of

most prenatal care. White births were 60 percent more likely

than black births to have received most prenatal care from a

private doctor (75 percent versus 46 percent). Thus, a majority

of black women relied on clinics for their prenatal care. Within

each category of birth characteristics presented in these tables,

white births were substantially more likely to have received

private care than black births, and the patterns of associations

were similar. There was a 20 percentage point difference in the

rates of private prenatal care between black (38 percent) and

white (58 percent) never-married women. Among births that

were intended at the time of conception, nearly 80 percent of

15
white births, compared with 50 percent of black births, received

private prenatal care. These findings reinforce the known

disparities in social and economic conditions surrounding

black and white childbearing (8,13,20).

Characteristics of the mother

The percent distribution of the source of most prenatal

care for all births according to selected maternal characteristics is shown in table 10. Births to minority women were much

less likely than those to non-Hispanic white women to receive

prenatal care primarily from private physicians. About 78 percent of white births, 53 percent of Hispanic births, and only

45 percent of black births received private care. Reliance on

clinics for prenatal care was comparable among births to

Hispanic and non-Hispanic black women, and more likely

than it was among births to non-Hispanic white women.

Private prenatal care was strongly linked with several

measures of socioeconomic status. Overall, the rate of clinic

use for prenatal care was 31 percent. Greater clinic reliance

was found among women who had less than a high school

education (50 percent), who had never worked (64 percent),

who had low income (47 percent), and who had received

Medicaid payments for prenatal care or delivery (72 percent).

Women who lived in central cities of metropolitan areas were

substantially more likely to use clinics (44 percent) than those

who lived in suburban or nonmetropolitan areas (27 percent).

Race-specific data for source of most prenatal care among

black and white births according to maternal characteristics

are shown in figure 3 and tables 11 and 12. As with the tables

presenting pregnancy and birth characteristics, the patterns of

associations were generally comparable between white and

black births. However, the extent of private prenatal care was

markedly greater among white births in nearly every category

of the maternal variables. For example, among births to

higher-educated women, private doctors were used for prenatal care for 84 percent of white births, compared with only

59 percent of black births. A 17 percentage point difference

(53 versus 36) was seen between white and black births

among women who never worked.

A somewhat different pattern in metropolitan residence

was suggested. For white births, lowest receipt of private

prenatal care was observed among women who lived in central

cities of metropolitan areas (65 percent). In contrast, for black

births, lower but similar rates of private care were found

among women living in either central cities or nonmetropolitan areas (43–45 percent).

Summary

Use of clinics for most prenatal care was more common

among the following groups of pregnant women:

+ never married

+ teenaged

+ Hispanic and non-Hispanic black

+ having an unwanted birth

+ delaying first prenatal visit beyond first trimester

+ low income (less than 150 percent of poverty level)

+ Medicaid recipient

+ never worked

+ education less than high school

Given that most women who receive delayed prenatal care

received their care at public clinics, greater outreach by clinics

and better tailoring of services might increase the proportions

receiving early care. For example, health planners and providers could consider increasing the number of facilities and staff,

boosting clinic hours, and providing assistance with transportation and child care (8,13).

Cigarette smoking during pregnancy

Smoking cigarettes during pregnancy has been shown to

increase the risk of numerous adverse pregnancy outcomes,

including low birthweight, preterm delivery, miscarriage, ectopic

(tubal) pregnancy, premature rupture of membranes, infant

death (for example, sudden infant death syndrome), low Apgar

scores, and early childhood illness (for example, respiratory

illnesses, asthma) (15,35,65–69). Risk of poor outcomes

increases with the amount smoked, but any amount of smoking increases risk relative to not smoking at all. Among studies

that considered passive exposure to cigarette smoke, exposure

in utero remained a significant risk factor for poor outcomes,

independent of other variables (32).

The biological mechanisms for the effect of smoking on

pregnancy loss, preterm delivery, and birthweight are known.

In addition, similar patterns of associations have been found

between smoking and low birthweight in countries with a wide

range of smoking prevalence (70). Biological plausibility and

generalizability of association are two key criteria for establishing causation (71), and these criteria appear to be met with

smoking.

Epidemiologic studies have established that smoking is

strongly associated with low birthweight that ensues from

intrauterine growth retardation (IUGR), also known as ‘‘term

low birthweight’’ and ‘‘small for gestational age’’ (SGA)

(72,73). The association with smoking is less strong for low

birthweight that results from preterm delivery, for which the

key predictors include older maternal age and prior preterm

delivery (15,74). Several components of cigarette smoke, such

as nicotine, have been demonstrated to reduce fetal growth,

leading to IUGR low birthweight, and to induce placental

insufficiency, leading to preterm delivery (69,75).

The causal role of maternal cigarette smoking is more

difficult to establish for child health after birth because of the

many family, socioeconomic, and environmental factors that

can confound the observed associations. However, some studies have suggested that smoking has adverse health and

developmental effects on young children (15,76,77).

Smoking among American women has generally been

declining in recent years, but these declines have been slower

or nonexistent among groups of women already at greater risk

of poor health outcomes (for example, teenaged white women,

poor women of all races) (78–80). Data from the 1987

Oklahoma Pregnancy Risk Assessment Monitoring System

(PRAMS) indicated that women receiving publicly funded

16
prenatal care (that is, care from a health department or paid by

Medicaid) were much more likely than other pregnant women

to smoke heavily before pregnancy and to continue smoking

during pregnancy (58).

Several reports have documented that women who smoke,

and particularly those who smoke during pregnancy, are more

likely to have other sociodemographic and behavioral attributes

that place them at higher risk for poor pregnancy outcomes

(16,56–58,65,79,81,82). However, smoking generally remains

an independent risk factor after adjustment for these other

characteristics. For example, smoking was found to reduce

birthweight by 150–300 grams (69) and to double the risk of

low birthweight, independent of other risk factors (81). It has

been estimated that elimination of smoking during pregnancy

would prevent 18 percent of low birthweight among singleton

white births and 35 percent among singleton black births (83).

The NSFG data in tables 13–18 show patterns of smoking

during pregnancy according to selected pregnancy and maternal characteristics. Women who had ever been pregnant and

who reported smoking at all in the 12 months prior to the

outcome of their most recent pregnancy, were asked:

‘‘On the average, how many cigarettes did you smoke per

day before you found out you were pregnant?’’ The answer

categories were:

+ about one a day or less

+ just a few (2–4)

+ about half a pack (5–14)

+ about a pack (15–24)

+ about 1 1/2 packs (25–34)

+ about 2 packs (35–44)

+ more than 2 packs (45 and more)

+ none

Women who reported smoking about half a pack (5–14

cigarettes) or less per day are shown in tables 13–18 as having

smoked fewer than 15 per day and are referred to in the text as

light smokers. Women who reported smoking about a pack

(15–24) or more per day are shown as having smoked 15 or

more per day and are referred to as heavy smokers in the text.

Women whose most recent completed pregnancy ended with

induced abortion are excluded from these tables.

Characteristics of the pregnancy

Overall, 28 percent of women reported smoking during

their most recent pregnancy, 17 percent were light smokers

and 11 percent were heavy smokers (table 13). The racespecific tables (tables 14 and 15) indicated that white women

were more likely to have smoked during pregnancy than black

women were (29 versus 24 percent), and all of this difference

was in heavy smoking (12 percent of white versus only

6 percent of black women).

Table 13 shows that for women of all races, smoking

during pregnancy generally diminishes with age, from 32 percent among teenaged women to 19 percent among women 30

years or older. However, tables 14 and 15 disclosed an

important race disparity in pregnancy-related smoking patterns

by age. No consistent relationship with age was seen among

black women, but the smoking rates for white women fell

sharply with age, from 39 percent among teenagers to 19 percent among older white women. These race differentials in

overall and age-related rates of smoking during pregnancy are

consistent with reports based on other surveys (43,56,79,80).

White and black women whose last pregnancy was third

or higher order were equally likely (30 percent) to report

smoking during the pregnancy. At each pregnancy order

(gravidity), black women had lower levels of heavy smoking

than white women did (for example, 4 percent versus 11 percent for primigravida).

Recency of the pregnancy was found to be related to the

overall and race-specific smoking rates. In addition to the data

in tables 13–15, table B shows that smoking during pregnancy

fell substantially from 35 percent among pregnancies ending

in 1970 or earlier to less than 25 percent among pregnancies

ending 1985–88. Because the data in table B come from

Cycles III and IV, it is possible that there was a ‘‘cycle effect’’

on smoking rates. This possibility was ruled out by checking

the smoking rates for pregnancies ending in 1971–80 in each

survey sample. The rates of smoking during pregnancy were

similar (30–32 percent) in both Cycles III and IV. The data in

table B suggest that public health messages urging smoking

cessation in pregnancy are having an impact. Also, the levels

of pregnancy-related smoking found in the NSFG are within

the range of other national estimates (80). The reduction in

smoking was more significant among white (34 to 25 percent)

(table 14) than among black women (25 to 20 percent)

(table 15). Despite these reductions over time, table B indicates that non-Hispanic white women continue to have higher

reported rates of smoking during pregnancy than non-Hispanic

black or Hispanic women.

Other pregnancy factors associated with higher smoking

rates among women, all races taken together (table 13), were

never-married status (34 versus 26 percent) and unwanted

status (34 percent versus 24 percent among intended pregnancies). The data suggested that smoking was more likely among

pregnancies ending in spontaneous loss than live birth (5 percentage point difference), and those receiving delayed or no

prenatal care than those with first trimester care (5 percentage

point difference). Tables 14 and 15 indicated that race-specific

patterns of smoking were similar, but that the associations

with smoking rates among black women were not statistically

significant for marital status, wantedness status, live birth

versus spontaneous loss, and timing of first prenatal visit.

Characteristics of the mother

Tables 16–18 present pregnancy-related smoking rates for

the most recently completed pregnancy by characteristics of

the mother. Hispanic women were less likely to have smoked

during pregnancy than non-Hispanic white or black women

(14 percent versus 30 and 23 percent, respectively). As found

in other reports (43,56,58,79), smoking in pregnancy was

related to many of the factors associated with smoking among

women in general—lesser education, lower-status jobs, and

lower income levels.

17
Table 16 shows large differences in smoking during pregnancy by education, and smaller but significant differences by

occupation and income level. Women with less than a high

school education were more than twice as likely to have

smoked during pregnancy than women with greater than a

high school education (43 versus 18 percent). Professional

women were less likely to have smoked (19 percent) than

women in other occupations (26–37 percent). Low-income

women were more likely to have smoked (34 percent) than

higher-income women (about 25 percent).

Heavy smoking during the most recent pregnancy was

more likely among non-Hispanic white women (14 percent),

less educated women (13–18 percent), those in lower-status

(that is, lesser paying) jobs (14–17 percent), and those with

low and middle incomes (less than 300 percent of poverty

level) (12 percent). Only 6 percent of women with more than a

high school education smoked heavily, as compared with

18 percent of women with less than a high school education.

The gap was even wider for white women taken separately

(6 versus 21 percent, table 17).

Tables 17 and 18 indicate similar patterns of associations

with maternal variables for white and black women; however,

the levels of smoking—especially heavy smoking—are generally lower for black women in every category. Smoking rates

dropped sharply as education increased among white women,

but among black women, the only significant reduction was

found between women who did not complete high school and

women who did (figure 4). A similar pattern occurred with

income level. For white women, there were significant declines

with each level of increasing income, while for black women,

the only significant decline in smoking rates was seen between

the lowest and middle income groups.

Trends: Cycles III–IV

Table B and figure 5 present the trends in smoking during

pregnancy for pregnancies ending in 1970 or before, 1971–80,

1981–84, and 1985–88, by selected characteristics of the

pregnancy and the mother. Overall, the rates of smoking fell

markedly from 35 percent among pregnancies ending in 1970

or earlier to 23 percent in those ending in 1985–88. Over time,

smoking in pregnancy has decreased in most subgroups of

women. However, several patterns persist. Smoking in pregnancy remains primarily a practice of women who are younger

(less than 25 years old), never married, having an unwanted

pregnancy, less educated, and lower income. With the exception of pregnancies in 1970 or earlier, Hispanic women had

lower smoking rates than women of other race/origins.

Overall age-specific smoking rates fell steadily throughout the 1970’s and 1980’s with one notable exception. Teenagers showed a considerable increase in smoking during

pregnancy in the 1970’s, from 34 to 45 percent. The age gap in

smoking widened substantially in the 1970’s and early 1980’s

(16 and 23 percentage point differences, respectively), but it

narrowed to a 12 percentage point difference among pregnancies ending in 1985–88.

Summary

NSFG data indicate that, overall, women are getting the

message about the harmful effects of smoking; smoking rates

during pregnancy have fallen steadily throughout the past two

decades. Yet, smoking in pregnancy continues to be a common

practice among the following groups of women:

+ never married

+ age less than 25 years

+ having an unwanted or mistimed birth

+ delaying first prenatal visit beyond first trimester

+ non-Hispanic white (especially heavy smoking)

+ low income (less than 150 percent of poverty level)

+ never worked or working in lower-status jobs

+ education less than high school

The persistence of pregnancy-related smoking among groups

of women who may already be at greater risk of poor health

and pregnancy outcomes suggests that health education and

smoking cessation programs should be targeted to these at-risk

groups.

Drinking during pregnancy

Heavy alcohol consumption during pregnancy increases

the risks for spontaneous pregnancy loss, particularly stillbirth.

Children of heavy drinkers have higher rates of birth defects,

low birthweight, pre- and postnatal growth retardation, mental

retardation, learning disorders, hyperkinetic disorders, and

perinatal mortality (13,84–87). Babies of alcoholic mothers

are often born with fetal alcohol syndrome, which involves

several of these conditions (84).

Unlike smoking during pregnancy, for which adverse

effects have been documented for any degree of exposure,

there has been considerable debate regarding the critical

threshold of alcohol consumption that leads to poor outcomes.

Numerous papers have suggested that other variables and

reporting errors in the amount of alcohol consumed may

prevent clear interpretation of the effects of alcohol use in

pregnancy (86–89). Heavy consumption is generally defined

as greater than 140–150 grams of absolute alcohol per week

(about 5 ounces), but elevated risk of pregnancy loss and low

birthweight have been found at more moderate levels of

consumption (87,90,91). Some have suggested that underreporting of alcohol consumption may result in a greater likelihood of mistakenly inferring negative effects of lower levels

of alcohol consumption (88). Further research is needed on the

following questions, among others:

+ How much alcohol consumption will adversely affect a

baby?

+ What are the effects of various drinking patterns (for

example, the effects of ‘‘binge drinking’’ versus ‘‘social

drinking’’)?

+ What are the effects of different types of alcohol (beer,

wine, liquor)?

+ What are the effects of the timing of fetal exposure to

alcohol?

18
+ What other variables must be controlled to accurately

measure alcohol’s effects (84,89)?

Although numerous issues remain unresolved about alcohol in pregnancy, the American Medical Association has

concluded that until a safe amount of consumption can be

firmly established, pregnant women should not drink alcohol

(84). Similarly, in July 1981, the U.S. Surgeon General

advised physicians that ‘‘each patient should be told about the

risk of alcohol consumption during pregnancy and advised not

to drink alcoholic beverages’’ (92). More recently, warning

labels were mandated for alcoholic beverage packaging.

Tables 19 and 20 present 1988 NSFG data on drinking

during the most recently completed pregnancy ending in

spontaneous loss or live birth. Women who had ever been

pregnant were asked: ‘‘On the average, how often did you

drink alcoholic beverages after you found out you were

pregnant?’’ The answer categories were:

+ every day

+ a few days a week

+ once a week

+ once a month

+ less than once a month

+ never

In the 1982 NSFG report, tables were presented with the

following categories of drinking frequency: ‘‘none,’’ ‘‘less

than once a week,’’ and ‘‘once a week or more often.’’ The

1988 data indicated a marked reduction in reports of drinking

more frequently than once a week, so tables 19 and 20 use the

following categories: ‘‘none,’’ ‘‘less than once a month,’’

‘‘once a month,’’ and ‘‘more than once a month.’’ For comparison across survey years, ‘‘more than once a month’’ in

tables 19 and 20 is equivalent to the ‘‘once a week or more

often’’ used in the 1982 report (22). ‘‘Regular’’ or ‘‘monthly’’

drinkers refer to women who drank once a month or more.

Table C shows the percent of women who drank alcohol

in any amount during their most recent pregnancy ending in

live birth or spontaneous loss. The overall percent fell from

45 percent in the 1982 NSFG to 34 percent in the 1988 NSFG.

Generally, the levels of reported drinking in pregnancy fell

between the two surveys, but the patterns of association with

maternal age, marital status, race/origin, education, and income

remained similar. Drinking during pregnancy was more common among women who were older, ever married, nonHispanic white, more educated, and higher-income. The

tendency for these women to have good pregnancy outcomes

despite their alcohol consumption may reflect their generally

good health status and access to health care. However, it may

also indicate that low levels of consumption are not necessarily harmful.

Characteristics of the pregnancy

Overall, 34 percent of pregnant women reported drinking

in their most recently completed pregnancy, and 15 percent

drank once a month or more (table 19). Drinking was somewhat less common in recent pregnancies (31 percent in 1985–

88) than in less recent pregnancies (37 percent before 1980)

(table 19). These figures, along with table C, suggest that

public health messages about abstinence during pregnancy

may be having an impact.

As found in other studies (79), table 19 shows that women

who drank during pregnancy were more likely to be older:

22 percent of teenage women drank while pregnant versus

37 percent of women 30 years or older. However, unlike other

studies that found lower parity among pregnant drinkers,

pregnant drinkers in the NSFG were more likely to be

multiparous than primiparous. Other, perhaps paradoxical,

findings suggested by the data were that drinkers were more

likely to be ever married than never married and that no

associations were disclosed with pregnancy loss, unwanted

status, or delayed initiation of prenatal care.

Black and white women showed similar drinking patterns

(not shown) by age, pregnancy order, year of pregnancy

outcome, and marital status, although the levels of drinking

are lower among black women in all categories of these

variables.

Characteristics of the mother

Non-Hispanic white women were more likely to have

consumed alcohol in their most recently completed pregnancy

than either Hispanic or non-Hispanic black women (table 20).

No difference was evident among monthly drinkers, which

implies that the higher amount of drinking among nonHispanic white women occurred chiefly in the ‘‘less than once

a month’’ category. About 21 percent of white women reported

drinking less than monthly, versus 11 percent of black women

and 13 percent of Hispanic women. This race/origin disparity

is consistent with findings from the 1982 NSFG and other

surveys (22,43,56). There was a striking pattern of an increased

proportion of women drinking less than once a month with

higher education: 12 percent of women with less than a high

school education, compared with 23 percent of women who

had some college, drank less than once a month during

pregnancy. Women in professional or managerial jobs were

twice as likely to have consumed alcohol as women who had

never worked (42 versus 20 percent). Women in other job

categories were intermediate in their proportions who drank

during pregnancy. Higher-income women were also more

likely to drink than lower-income women (40 versus about

30 percent). All of these findings are consistent with the

association disclosed in numerous studies of drinking with

higher social status (82).

Measured by area of residence, the greatest proportion of

abstainers from alcohol was found among women living in

nonmetropolitan areas.

White and black drinking patterns (not shown) were

similar by maternal characteristics. One notable exception was

drinking patterns by educational level (figure 6). Overall,

15 percent of women, regardless of race, drank once a month

or more during pregnancy. Among white women, there was an

increase in drinking (once a month or more) with higher

education, from 11 to 20 percent. Among black women,

however, the data indicated a reverse pattern: 19 percent of

19
less-educated black women drank once a month or more

compared with 11 percent of black women with some college

education.

Summary

NSFG data from 1982 and 1988 suggest that reported

drinking during pregnancy has declined, but the decline is not

statistically significant at the 5-percent level. Drinking during

pregnancy, particularly light drinking, remains a practice of

the following groups of women:

+ older

+ non-Hispanic white, more educated

+ non-Hispanic black, less educated

+ higher income

+ higher status jobs

Though requiring multivariate analysis for confirmation, the

NSFG data suggested that these women’s overall good health,

access to health care, and nutrition may well overwhelm any

potentially adverse effects of light alcohol consumption. Conversely, it may be that light consumption is not harmful or is

only harmful when other factors associated with poor pregnancy and health outcomes are present. These data showed

that among black women, drinking during pregnancy is more

common among those with less education, lower incomes, and

lower-status or no jobs. Women in these socioeconomic groups

are already at significant risk for poor health outcomes.

Smoking and drinking during pregnancy

Table D shows the percent distribution of smoking and

drinking during the most recent pregnancy that ended in live

birth or spontaneous loss. About 51 percent of ever-pregnant

women abstained from both smoking and drinking during

pregnancy, 15 percent smoked only, 21 percent drank only,

and 12 percent both smoked and drank. No clear age pattern

could be detected for total abstinence, probably because the

patterns for smoking and drinking went in opposite directions.

Younger women tended to smoke and older women tended to

drink. Among women who reported both smoking and drinking, there was a modest decline after age 30.

Women with pregnancies ending more recently, particularly after 1980, were less likely to smoke or drink during

pregnancy. This suggests that public health messages are

having an impact on pregnant women and prenatal care

providers.

Non-Hispanic white women were significantly more likely

than Hispanic or non-Hispanic black women to smoke and/or

drink during pregnancy (54 versus 31 and 37 percent). Education was strongly correlated with drinking during pregnancy,

but showed a strong inverse correlation with smoking. Table D

indicates that women who smoke during pregnancy may not

be the same women who drink during pregnancy, so health

education efforts should not be targeted similarly.

Low birthweight

Low birthweight is defined as 2,500 grams (5 1/2 pounds)

or less (13). Babies born at low birthweight are significantly

more likely to die than normal weight babies during the first

28 days of life. They account for two-thirds of neonatal deaths

in the United States (8,13). After the neonatal period, lowbirthweight babies are twice as likely to be rehospitalized

during their first year and five times more likely to die

between 28 days and 1 year. They are at increased risk for

neurodevelopmental handicaps (for example, cerebral palsy,

seizure disorders), birth defects, childhood illnesses, learning

disorders, and social functioning and behavioral problems

(13,20,93,94). The risk of adverse consequences increases

substantially for very-low-birthweight babies, those born at

less than 1,500 grams. However, for this report, tabulations are

presented only for low-birthweight babies due to the small

numbers of very-low-birthweight births in the NSFG. Several

reports based on vital registration data can provide further

information on the risks associated with more severe low

birthweight (1,2,4,5,37,41).

Two major etiologic classes of low birthweight have been

identified: (a) term low birthweight, or ‘‘small for gestational

age’’ low birthweight, due to intrauterine growth retardation

(IUGR), and (b) preterm low birthweight results from premature delivery (earlier than 37 weeks gestation). In general,

preterm low birthweight is associated with higher perinatal

mortality, but those babies who survive the perinatal period

tend to catch up to the weight and developmental milestones

of their normal birthweight counterparts. Meanwhile, IUGR

low-birthweight babies have lower infant mortality rates than

preterm low-birthweight babies, but they are more likely to be

sick and rehospitalized in their first year of life and do not

catch up to normal birthweight babies (13,74).

Many of the same factors have been associated with term

(IUGR) and preterm low birthweight: younger and older

maternal age, prenatal stress, prior history of low-birthweight

births or pregnancy losses, lower pre-pregnancy weight, lack

of early and adequate prenatal care, unmarried status, black

race, lower levels of education and income, lower status jobs,

and smoking and drinking during pregnancy (73,95,96). Smoking has been particularly linked with IUGR low birthweight

(72).

Because many of these factors can be readily identified

before delivery, they can be used for screening and risk

assessment. Smoking and drinking during pregnancy, as well

as timing and adequacy of prenatal care, are the most amenable to preventive measures (8,13,20). Prevention of lowbirthweight births, and its adverse consequences, has immense

potential for reducing medical expenditures at personal (family) and governmental levels. In 1988, the Office of Technology Assessment estimated that for every immature birth (low

birthweight or preterm) prevented by improved prenatal care,

the U.S. health care system would save between $14,000–

$30,000 (20). Given medical cost inflation since 1988, these

figures are likely to be substantially higher now. Also, given

that a large proportion of low-birthweight infants are born to

poor or young mothers, many of whom do not have private

20
health insurance, the costs of low-birthweight care are often

passed on to the public (8).

In addition to the considerable research on the impact of

socioeconomic confounding on low-birthweight rates, some

researchers have suggested that part of the persisting racial

gap is due to differing birthweight distributions (97,98). Other

researchers have focused on the apparent fact that smaller

black babies are more likely to survive than white babies of

the same weight (that is, a birthweight-specific advantage for

black babies) (6,99). In a study of smoking and the risk for

sudden infant death syndrome (SIDS) among different racial

and ethnic groups, one report concluded that using the same

definition of low birthweight may explain the weaker association between smoking and SIDS for black babies and the lack

of association among Asian and Hispanic babies (100). Many

questions remain unanswered, including the persistence of a

nearly twofold race gap in birthweight-specific mortality, even

after using race-specific birthweight distributions. It may be

that any biological advantage of black babies (both low and

normal weight) is outweighed by social and economic disadvantage, as well as by differentials in behavioral risk factors.

Tables 21–24 present 1988 NSFG data on low birthweight

among all single live births. The tabulations in this report were

restricted to single live births because multiple births are far

more likely than single births to be low birthweight (101).

Characteristics of the birth

Table 21 shows that the overall rate of low birthweight

among single live births was 7 percent. The black rate of

14 percent was more than twice the white rate of 6 percent.

These figures are consistent with birth certificate data for

single live births in 1988 (41).

The rates for all races reflect the disproportionate contribution of white births to the denominator (all single live

births) and black low birthweight births to the numerator, so

the discussion of tables 21 and 22 will focus on the racespecific rates. The ‘‘all races’’ rates are presented because they

include births to women of other races.

The rates for low birthweight among black births were

generally higher, typically about double, the rates among

white births in all categories of the birth characteristics shown

(table 21). About 15 percent of black births to teenagers were

low birthweight, compared with 8 percent of white births to

teenagers. The sex differential in low birthweight suggested in

the overall group was more marked among black births—

nearly 18 percent of black female births were low birthweight

versus 11 percent of black male births. While white lowbirthweight rates declined from 7 percent to 5 percent by more

recent year of birth, the black low birthweight rate fell from

15 percent to 12 percent.

No significant difference in the percent low birthweight

was seen by marital status among black or white births

separately. However, when all races were considered together,

births to never-married women were more likely than those to

ever-married women to be low birthweight (11 versus 7 percent). This difference reflects, in part, the fact that a greater

proportion of black births than white births occur among

never-married mothers, and black births are significantly more

likely to be low birthweight. Along with race, many other

factors contribute to differentials in low-birthweight rate by

marital status. In one of the few multivariate analyses (to date)

of birth registration data, the Missouri State Health Department has used 1991 data to produce odds ratios for low

birthweight, adjusting for selected risk factors on the birth

certificate. Births to unmarried women were 19 to 42 percent

more likely to be low birthweight than births to married

women, after controlling for race, age, education, parity,

Medicaid status, maternal weight, history of premature delivery, history of infant/child death, pregnancy weight gain,

smoking during pregnancy, birth spacing, and initiation of

prenatal care (102). It should be noted that the NSFG did not

code precise marital status at the time of delivery; a certain

unknown fraction (and unknowable) fraction of ‘‘evermarried’’ births were to women who were not currently

married. A further note of caution about interpreting these

findings is that the Missouri analysis was limited to those risk

factors available on the birth certificate. These do not comprise

a complete roster of variables to account for the indirect effect

of marital status on pregnancy outcome.

With regard to wantedness status, a greater proportion of

black births than white births were mistimed or unwanted at

the time of conception. This was linked to significantly higher

rates of low birthweight among black births and total (all

races) births. White births that were unwanted or mistimed

were no more likely to be low birthweight than white births

that were intended. The lack of bivariate association between

birthweight and prenatal care initiation may be related to the

absence of more precise measures of prenatal care adequacy in

the NSFG, such as timing and content of subsequent visits.

A somewhat different racial pattern in low birthweight

rates was seen with source of prenatal care. Highest low

birthweight rates were found among white women who attended

hospital clinics, while for black women, the data suggested

higher low birthweight rates among those attending either

hospital or other clinics. This racial difference may be caused

by a higher proportion of black mothers than white mothers

relying on nonhospital (that is, other) clinics for prenatal care.

White mothers using hospital clinics rather than private doctors for prenatal care may have been referred there because

such clinics are often targeted at women who are at medically

higher risk for poor outcomes, such as low birthweight.

However, black mothers receiving prenatal care from clinics

are, in general, more likely to be in groups at higher risk for

low birthweight, both for medical and nonmedical reasons.

For example, their access to and use of health services may be

limited by their lower, on average, levels of income or

education.

Low-birthweight rates rose with increased amounts of

cigarette smoking during pregnancy for white and black

women (4–9 percent and 11–21 percent, respectively) (figure 7). The rates of low birthweight were significantly higher

for black mothers in each smoking category.

21
Characteristics of the mother

Table 22 shows that non-Hispanic black births were more

than twice as likely to be low-birthweight (14 percent) as

births to Hispanic and non-Hispanic white women (6 percent)

and other race women (7 percent).

The race-specific low-birthweight rates in table 22 indicate similar patterns between white and black births, but much

higher rates of low birthweight among black births. As seen

with several of the birth characteristics, the approximately

twofold disparity in low-birthweight rates was maintained

across all categories of maternal variables. Sample sizes were

too small for the differences to be statistically significant

among black births, but higher low-birthweight rates in both

race groups were found for women who were less educated,

had lower status jobs or never worked, or had lower incomes.

Birth registration data support the association between lowbirthweight and lower educational attainment, but income and

occupation data cannot be compared because they are unavailable from vital statistics (37).

Trends: Cycles III–IV

Tables 23 and 24 illustrate trends in low-birthweight

among single live births based on the 1982 and 1988 NSFG.

Low birthweight rates have fallen substantially over time,

reflecting medical and public health advances: 16 percent

among single live births in 1970 or earlier, to 6 percent among

births in 1985–88. (The possibility of a ‘‘cycle effect’’ on

low-birthweight rates in tables 23 and 24 was eliminated by

checking the low-birthweight rates for single live births in

1971–80 in each survey sample. The rates of low birthweight

were similar (7–9 percent) in both Cycles III and IV.) During

the earlier years, an association between smoking and lowbirthweight rates was not detectable. However, as lowbirthweight rates fell, particularly for births in 1985–88, the

rates were significantly higher among women who smoked

during pregnancy (about 11 percent) than among nonsmokers

(4 percent) (table 23).

Summary

Although low-birthweight rates have fallen over time,

tables 23 and 24 show that higher rates continue to be found

among mothers who are:

+ teenaged

+ having a higher order birth

+ never married

+ having an unwanted birth

+ black

+ less educated

+ lower income

+ residents of central metropolitan areas

Source of payment for delivery

Several reports, including those based on the 1984 National

Health Interview Survey (103), have documented that white

persons aged 18–44 years are more likely to have private

medical insurance than black persons aged 18–44 years.

Because health insurance is predominantly a benefit of employment, this disparity in insurance coverage is primarily linked

with racial differentials in work status (that is, whether and

how employed), which in turn are associated with differentials

in education and other socioeconomic factors. Proportions

covered by private medical insurance rise with education and

income level. The NSFG is one of the few nationally representative sources of data on payment for delivery costs and the

only national survey that collected this data throughout the

1970’s and 1980’s. Tables 25–32, which present NSFG data

on payment for delivery, permit an examination of these

associations among childbearing women in the United States.

Tables 25–30 give the percents who used any of the specified

sources to pay for live birth deliveries between 1984 and 1988.

The percents sum to more than 100 percent because women

could report more than one form of payment. Tables 31–32

show the percent distribution, summing to 100 percent, by

source of payment for most recent delivery (1984–88).

Characteristics of the birth

Among all live births occurring in 1984–88, 44 percent of

the deliveries were paid for by the woman, her family, or

friends (that is, out of pocket); 66 percent by private medical

insurance; 11 percent by Medicaid; and 9 percent by other

government sources (table 25). The racial disparities (tables

26–27) were striking. Private insurance was used for 71 percent of white deliveries versus 40 percent of black deliveries.

Medicaid paid for 7 percent of white deliveries, compared

with 33 percent of black deliveries. Because insurance generally pays for part but not all medical expenses and because

white women were more likely to have private insurance

coverage, it is not surprising that white women were more

likely (47 percent) than black women (27 percent) to use

out-of-pocket funds to pay for part of the delivery costs. In

general, for this reason, out-of-pocket payment patterns mirrored those of private insurance.

Reliance on private insurance was greatest among women

who were older, who had deliveries by cesarean section, who

were ever married, who intended their pregnancies at the time

of conception, whose prenatal care began in the first trimester,

and whose prenatal care came mostly from private physicians.

The associations with age and marital status were particularly

striking.

Insurance paid, all or in part, for 30 percent of teenagers’

deliveries versus 82 percent of deliveries to women 30 years

or older. About 74 percent of deliveries to ever-married women

had insurance coverage, compared with 23 percent to nevermarried women. About 73 percent of those with first trimester

prenatal care used private insurance to pay for the birth,

compared with only 47 percent of those with late or no

prenatal care. Women who received most of their prenatal care

from private physicians were more likely (78 percent) to use

insurance for delivery costs than women who used clinics

(34–42 percent). The data suggested that insurance coverage

was more likely for normal weight babies than for lowbirthweight babies. This is probably due to low-birthweight

22
being more prevalent among black babies, whose deliveries

were likely to be paid for in ways other than private insurance.

Conversely, Medicaid and other government payment was

more likely for deliveries to women who were younger, who

were never married, whose pregnancies were mistimed or

unwanted at conception, whose first prenatal visit was delayed

or never occurred, or whose prenatal care came mainly from

clinic providers (table 25, figure 10). Medicaid covered 30 percent of teenage deliveries, 38 percent of never-married deliveries, 21 percent of unwanted deliveries, 18 percent of deliveries

to women who received delayed or no prenatal care, and

24–30 percent of deliveries to women who attended clinics for

most of their prenatal care.

Tables 27 and 28 and figure 8 disclose some important

racial differentials in source of payment for delivery. Medicaid

and other government sources were the leading payment

source (44 and 21 percent, respectively) among births to black

teenagers, while out-of-pocket and private insurance were

primary sources for white teenagers (43 and 37 percent,

respectively). The leading payment sources for white lowbirthweight deliveries were private insurance (62 percent) and

out-of-pocket funds (41 percent), but the leading sources for

black low-birthweight deliveries were insurance (38 percent)

or Medicaid (35 percent). Never-married white women were

fairly evenly distributed across the forms of payment for

delivery, but the leading payment sources for never-married

black women were Medicaid (46 percent) and other government sources (22 percent).

Characteristics of the mother

Tables 28–30 show percents of all deliveries paid for by

specified sources according to characteristics of the mother at

time of interview. Hispanic and non-Hispanic black deliveries

were 4–6 times more likely than non-Hispanic white deliveries

to have been paid for by Medicaid, and twice as likely to be

paid for by other government sources. Conversely, reliance on

insurance was markedly greater among non-Hispanic white

women than among the other two groups (table 28). Insurance

payment was tied closely with measures of socioeconomic

status, increasing with higher education, higher status jobs,

higher income, and suburban residence. Deliveries to highincome women were over three times as likely to be paid for

by private insurance as deliveries to low-income women (89

versus 31 percent) (table 28). A similar pattern for educational

status was found. Over 90 percent of women in professional or

managerial jobs had their deliveries paid for by insurance as

compared with 58 percent of women in service, farm, craft, or

operative jobs and 32 percent of women who never worked.

The data suggested that Medicaid covered a greater percent of

deliveries in central cities of metropolitan areas.

As with the birth characteristics, source of delivery payment according to maternal characteristics revealed substantial

racial disparities. Insurance coverage showed similar patterns

of association with higher education, higher status jobs, higher

income, and suburban residence.

However, the level of use of insurance was dramatically

lower among black than among white women. Even among

college-educated women, 85 percent of white women and only

68 percent of black women used private insurance for their

delivery costs—a difference of nearly 20 percentage points.

This finding gives further evidence of continuing socioeconomic disparities between black and white college-educated

women (95). Insurance paid for deliveries of only 56 percent

of white women living in central cities of metropolitan areas,

76 percent of white women living in suburban areas, and

69 percent of white women living in nonmetropolitan areas;

the parallel percents for black women were 36, 50, and 33.

Percent distribution by source of payment

Tables 31 and 32 show the percent distribution by source

of payment for most recent deliveries between 1984 and 1988.

The categories were own income only (‘‘self, family, or

friends’’), insurance only, own income and insurance only,

Medicaid only, other government sources only, and all other

combinations of sources. The tables were restricted to the most

recent delivery to avoid over-representation of high-parity

women, who are more likely to have their births closer

together and to be of lower socioeconomic status (that is, use

Medicaid or other government sources).

One purpose of this categorization was to distinguish

between women who relied solely on out-of-pocket funds and

those who use out-of-pocket funds to supplement insurance

coverage. It was expected that the two groups would show

marked socioeconomic differences, and the data supported this

hypothesis. Sole reliance on out-of-pocket funds generally

mirrored the patterns of payment by Medicaid or other government sources. Women using Medicaid, other government

sources, or only their own funds were more likely to be

younger (less than 25 years old), never married (figure 9), to

be having a first birth or a third-or-higher order birth, to be

having an unwanted or mistimed birth, to have delayed or

have no prenatal care for this birth, or to have obtained most

prenatal care from clinic providers. Maternal characteristics

associated with these forms of payment included less education, having never worked or working in lower status jobs, and

lower income.

The exceptions to the similarity of associations between

solely out-of-pocket payers and Medicaid/government payers

were with birthweight, marital status, race/origin, and metropolitan residence. Women who had low-birthweight babies

were somewhat less likely to use solely out-of-pocket funds

and more likely to use Medicaid or government funds, compared with women who had normal birthweight babies. No

difference by marital status (11 percent for both ever- and

never-married women) was seen for women relying solely on

out-of-pocket funds. Conversely, 34 percent of never-married

women used Medicaid only and 23 percent relied on other

government sources compared with 4 and 5 percent, respectively, among ever-married women (figure 9). Medicaid or

government fund usage was most likely for non-Hispanic

black or Hispanic women, and for women living in central

metropolitan areas. There was no clear pattern in use of solely

out-of-pocket funds by race/origin or metropolitan residence.

23
Reliance on private medical insurance, either alone or in

conjunction with out-of-pocket funds, was associated with

older age, normal birthweight, ever-married status, intended

births, early prenatal care, receipt of prenatal care from private

physicians, higher education, higher status jobs, higher income,

and residence in suburban or nonmetropolitan areas. These

data on source of payment for delivery document one of the

consequences of the socioeconomic disparities in insurance

status illustrated in other NCHS reports (104).

Summary

The use of private insurance and Medicaid for delivery

costs did not change significantly between the 1982 and 1988

NSFG (table E). The strongest correlates of private insurance

use continue to be older age, ever-married status, employment

(especially in higher paying jobs), and white race. Racial

differentials in insurance use persist even among women of

equal educational and occupational status. Medicaid, other

government funds, and out-of-pocket funds remain the leading

sources of payment for births to teenagers and never-married

women.

24
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27
List of detailed tables

1. Number of pregnancies ending in a live birth in January

1984 or later to women 15–44 years of age and percent

distribution by months pregnant when prenatal care began,

according to selected characteristics of the birth: United

States, 1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2. Number of pregnancies ending in a live birth in January

1984 or later to white women 15–44 years of age and

percent distribution by months pregnant when prenatal

care began, according to selected characteristics of the

birth: United States, 1988 . . . . . . . . . . . . . . . . . . . . . . . 31

3. Number of pregnancies ending in a live birth in January

1984 or later to black women 15–44 years of age and

percent distribution by months pregnant when prenatal

care began, according to selected characteristics of the

birth: United States, 1988 . . . . . . . . . . . . . . . . . . . . . . . 32

4. Number of pregnancies ending in a live birth in January

1984 or later to women 15–44 years of age and percent

distribution by months pregnant when prenatal care began,

according to selected characteristics of the mother: United

States, 1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

5. Number of pregnancies ending in a live birth in January

1984 or later to white women 15–44 years of age and

percent distribution by months pregnant when prenatal

care began, according to selected characteristics of the

mother: United States, 1988 . . . . . . . . . . . . . . . . . . . . . 34

6. Number of pregnancies ending in a live birth in January

1984 or later to black women 15–44 years of age and

percent distribution by months pregnant when prenatal

care began, according to selected characteristics of the

mother: United States, 1988 . . . . . . . . . . . . . . . . . . . . . 35

7. Number of pregnancies ending in live birth in January

1984 or later to women 15–44 years of age, percent

receiving prenatal care, and percent distribution of pregnancies receiving care by source of care for most prenatal

visits, according to selected characteristics of the birth:

United States, 1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

8. Number of pregnancies ending in live birth in January

1984 or later to white women 15–44 years of age, percent

receiving prenatal care, and percent distribution of pregnancies receiving care by source of care for most prenatal

visits, according to selected characteristics of the birth:

United States, 1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

9. Number of pregnancies ending in live birth in January

1984 or later to black women 15–44 years of age, percent

receiving prenatal care, and percent distribution of pregnancies receiving care by source of prenatal care for most

visits, according to selected characteristics of the birth:

United States, 1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

10. Number of pregnancies ending in a live birth in January

1984 or later to women 15–44 years of age, percent

receiving prenatal care, and percent distribution of pregnancies receiving care by source of care for most prenatal

visits, according to selected characteristics of the mother:

United States, 1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

11. Number of pregnancies ending in a live birth in January

1984 or later to white women 15–44 years of age, percent

receiving prenatal care, and percent distribution of pregnancies receiving care by source of care for most prenatal

visits, according to selected characteristics of the mother:

United States, 1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

12. Number of pregnancies ending in a live birth in January

1984 or later to black women 15–44 years of age, percent

receiving prenatal care, and percent distribution of pregnancies receiving care by source of care for most prenatal

visits, according to selected characteristics of the mother:

United States, 1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

13. Number of women 15–44 years of age whose most recent

pregnancy ended in live birth or spontaneous loss and

percent distribution by average number of cigarettes

smoked per day during the pregnancy, according to

selected characteristics of the pregnancy: United States,

1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

14. Number of white women 15–44 years of age whose most

recent pregnancy ended in live birth or spontaneous loss

and percent distribution by average number of cigarettes

smoked per day during the pregnancy, according to

selected characteristics of the pregnancy: United States,

1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

15. Number of black women 15–44 years of age whose most

recent pregnancy ended in live birth or spontaneous loss

and percent distribution by average number of cigarettes

smoked per day during the pregnancy, according to

selected characteristics of the pregnancy: United States,

1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

16. Number of women 15–44 years of age whose most recent

pregnancy ended in live birth or spontaneous loss and

percent distribution by average number of cigarettes

smoked per day during the pregnancy, according to

selected characteristics of the mother: United States,

1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

17. Number of white women 15–44 years of age whose most

recent pregnancy ended in live birth or spontaneous loss

and percent distribution by average number of cigarettes

smoked per day during the pregnancy, according to

selected characteristics of the mother: United States,

1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

18. Number of black women 15–44 years of age whose most

recent pregnancy ended in live birth or spontaneous loss

and percent distribution by average number of cigarettes

smoked per day during the pregnancy, according to

selected characteristics of the mother: United States,

1988 ...................................... 47

19. Number of women 15–44 years of age whose most recent

pregnancy ended in live birth or spontaneous loss and

percent distribution by average frequency of alcoholic

beverage consumption during the pregnancy, according to

selected characteristics of the pregnancy: United States,

1988 ...................................... 48

20. Number of women 15–44 years of age whose most recent

pregnancy ended in live birth or spontaneous loss and

percent distribution by average frequency of alcoholic

28
beverage consumption during the pregnancy, according to

selected characteristics of the mother: United States,

1988 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

21. Number of single live births to women 15–44 years of age

and percent low birthweight, by race and selected characteristics of the birth: United States, 1988 . . . . . . . . . . . 50

22. Number of single live births to women 15–44 years of age

and percent low birthweight, by race and selected characteristics of the mother: United States, 1988 . . . . . . . . . 51

23. Number of single live births to women 15–44 years of age

and percent low birthweight, according to year of birth

and selected characteristics of the birth: United States . 52

24. Number of single live births to women 15–44 years of age

and percent low birthweight, by year of birth and selected

characteristics of the mother: United States . . . . . . . . . 53

25. Number of live birth deliveries in January 1984 or later to

women 15–44 years of age and percent of delivery costs

paid from specified sources, by selected characteristics of

the birth: United States, 1988 . . . . . . . . . . . . . . . . . . . 54

26. Number of live birth deliveries in January 1984 or later to

white women 15–44 years of age and percent of delivery

costs paid from specified sources, by selected characteristics of the birth: United States, 1988 . . . . . . . . . . . . . 55

27. Number of live birth deliveries in January 1984 or later to

black women 15–44 years of age and percent of delivery

costs paid from specified sources, by selected characteristics of the birth: United States, 1988 . . . . . . . . . . . . . 56

28. Number of live birth deliveries in January 1984 or later to

women 15–44 years of age and percent of delivery costs

paid from specified sources, by selected characteristics of

the mother: United States, 1988 .................. 57

29. Number of live birth deliveries in January 1984 or later to

white women 15–44 years of age and percent of delivery

costs paid from specified sources, by selected characteristics of the mother: United States, 1988 ........... 58

30. Number of live birth deliveries in January 1984 or later to

black women 15–44 years of age and percent of delivery

costs paid from specified sources, by selected characteristics of the mother: United States, 1988 ........... 59

31. Number of women 15–44 years of age who had a live

birth in January 1984 or later and percent distribution by

source of payment for most recent delivery, according to

selected characteristics of the birth: United States,

1988 ...................................... 60

32. Number of women 15–44 years of age who had a live

birth in January 1984 or later and percent distribution by

source of payment for most recent delivery, according to

selected characteristics of the mother: United States,

1988 ...................................... 61

29
Table 1. Number of pregnancies ending in a live birth in January 1984 or later to women 15–44 years of age and percent distribution by

months pregnant when prenatal care began, according to selected characteristics of the birth: United States, 1988

Characteristic of the birth

Number in

thousands Total

Months pregnant when prenatal care began

Less than

3 months

3–4

months

5 months or

more or no care

Percent distribution

All pregnancies ending in a live birth1 .......... 16,220 100.0 65.4 19.3 15.3

Mother’s age at time of birth

Under 20 years ....................... 1,823 100.0 39.2 30.4 30.5

20–24 years ......................... 4,562 100.0 59.6 22.7 17.7

25–29 years ......................... 5,627 100.0 72.9 17.1 10.0

30–44 years ......................... 4,208 100.0 73.0 13.8 13.2

Birth order

First .............................. 4,881 100.0 66.5 19.7 13.8

Second ............................ 4,856 100.0 69.5 17.9 12.7

Third or higher ........................ 6,482 100.0 61.5 20.1 18.4

Mode of delivery

Cesarean section ...................... 3,789 100.0 66.3 19.7 14.0

Vaginal ............................ 12,379 100.0 65.2 19.0 15.8

Mother’s marital status at time of birth

Never married ........................ 2,695 100.0 45.9 23.9 30.3

Ever married ......................... 13,526 100.0 69.3 18.4 12.3

Wantedness status at conception

Intended ............................ 9,711 100.0 71.9 16.3 11.8

Mistimed ........................... 4,487 100.0 55.9 25.4 18.7

Unwanted ........................... 1,987 100.0 55.1 20.3 24.7

1Includes births with missing data on first prenatal care visit, mode of delivery, or wantedness status.

30
Table 2. Number of pregnancies ending in a live birth in January 1984 or later to white women 15–44 years of age and percent

distribution by months pregnant when prenatal care began, according to selected characteristics of the birth: United States, 1988

Characteristic of the birth

Number in

thousands Total

Months pregnant when prenatal care began

Less than

3 months

3–4

months

5 months or

more or no care

Percent distribution

All pregnancies ending in a live birth1 .......... 12,821 100.0 67.9 18.1 14.0

Mother’s age at time of birth

Under 20 years ....................... 1,144 100.0 41.7 32.1 26.2

20–24 years ......................... 3,476 100.0 60.0 21.9 18.1

25–29 years ......................... 4,726 100.0 74.0 16.0 9.9

30–44 years ......................... 3,474 100.0 76.0 12.6 11.4

Birth order

First .............................. 3,815 100.0 69.3 18.0 12.7

Second ............................ 3,899 100.0 72.5 17.4 10.0

Third or higher ........................ 5,107 100.0 63.2 18.7 18.0

Mode of delivery

Cesarean section ...................... 2,965 100.0 68.0 19.4 12.6

Vaginal ............................ 9,809 100.0 68.0 17.6 14.5

Mother’s marital status at time of birth

Never married ........................ 1,220 100.0 45.4 19.5 35.1

Ever married ......................... 11,601 100.0 70.2 18.0 11.8

Wantedness status at conception

Intended ............................ 8,056 100.0 73.8 15.4 10.8

Mistimed ........................... 3,546 100.0 57.4 24.9 17.7

Unwanted ........................... 1,193 100.0 59.0 16.7 24.3

1Includes births with missing data on first prenatal care visit, mode of delivery, or wantedness status.

31
Table 3. Number of pregnancies ending in a live birth in January 1984 or later to black women 15–44 years of age and percent

distribution by months pregnant when prenatal care began, according to selected characteristics of the birth: United States, 1988

Characteristic of the birth

Number in

thousands Total

Months pregnant when prenatal care began

Less than

3 months

3–4

months

5 months or

more or no care

Percent distribution

All pregnancies ending in a live birth1 .......... 2,374 100.0 53.6 26.1 20.3

Mother’s age at time of birth

Under 20 years . . . . . . . . . . . . . . . . . . . . . . . 576 100.0 36.7 27.8 35.4

20–24 years . . . . . . . . . . . . . . . . . . . . . . . . . 777 100.0 54.7 27.5 17.8

25–29 years . . . . . . . . . . . . . . . . . . . . . . . . . 587 100.0 63.6 25.3 11.2

30–44 years . . . . . . . . . . . . . . . . . . . . . . . . . 434 100.0 60.4 22.2 17.4

Birth order

First . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 719 100.0 51.8 28.8 19.3

Second . . . . . . . . . . . . . . . . . . . . . . . . . . . . 641 100.0 56.2 21.8 22.1

Third or higher ........................ 1,014 100.0 53.2 26.8 20.0

Mode of delivery

Cesarean section . . . . . . . . . . . . . . . . . . . . . . 555 100.0 56.4 26.3 17.3

Vaginal ............................ 1,814 100.0 52.7 25.9 21.3

Mother’s marital status at time of birth

Never married ........................ 1,323 100.0 48.6 26.5 24.9

Ever married ......................... 1,051 100.0 59.9 25.5 14.6

Wantedness status at conception

Intended . . . . . . . . . . . . . . . . . . . . . . . . . . . . 961 100.0 58.9 24.7 16.4

Mistimed . . . . . . . . . . . . . . . . . . . . . . . . . . . 729 100.0 51.1 28.3 20.6

Unwanted . . . . . . . . . . . . . . . . . . . . . . . . . . . 674 100.0 48.5 26.0 25.5

1Includes births with missing data on mode of delivery or wantedness status.

32
Table 4. Number of pregnancies ending in a live birth in January 1984 or later to women 15–44 years of age and percent distribution by

months pregnant when prenatal care began, according to selected characteristics of the mother: United States, 1988

Characteristic of the mother

Number in

thousands Total

Months pregnant when prenatal care began

Less than

3 months

3–4

months

5 months or

more or no care

Percent distribution

All pregnancies ending in a live birth1 .......... 16,220 100.0 65.4 19.3 15.3

Race and Hispanic origin

Hispanic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,115 100.0 52.6 23.1 24.3

Non-Hispanic white ..................... 11,025 100.0 70.3 17.4 12.2

Non-Hispanic black ..................... 2,287 100.0 52.7 26.5 20.8

Non-Hispanic other . . . . . . . . . . . . . . . . . . . . . 794 100.0 67.3 14.5 18.2

Education (at interview)2

Less than 12 years ..................... 2,557 100.0 49.1 20.7 30.2

12 years ............................ 5,287 100.0 66.5 22.4 11.1

13 years or more ...................... 6,554 100.0 78.1 13.2 8.7

Most recent occupation2

Professional or managerial ................ 2,928 100.0 79.4 14.5 6.1

Sales or clerical ....................... 5,921 100.0 70.8 17.5 11.7

Service ............................ 2,495 100.0 63.4 18.8 17.8

Farm, craft, or operative .................. 1,539 100.0 67.2 20.0 12.8

Never worked ........................ 1,515 100.0 50.2 22.4 27.4

Poverty level income (at interview)2

149 percent or less ..................... 3,908 100.0 52.8 22.8 24.4

150–299 percent ...................... 4,331 100.0 67.6 21.4 11.0

300 percent or more .................... 6,158 100.0 79.5 12.4 8.1

Medicaid for prenatal care or delivery

No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14,256 100.0 67.7 18.2 14.1

Yes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,964 100.0 48.7 27.6 23.7

Residence (at interview)

Metropolitan/central city .................. 3,764 100.0 61.2 20.4 18.4

Metropolitan/suburban ................... 8,630 100.0 70.1 16.6 13.4

Nonmetropolitan ....................... 3,827 100.0 58.9 24.4 16.7

1Includes births with missing data on first prenatal care visit.

2Limited to women 20–44 years at time of birth.

33
Table 5. Number of pregnancies ending in a live birth in January 1984 or later to white women 15–44 years of age and percent

distribution by months pregnant when prenatal care began, according to selected characteristics of the mother: United States, 1988

Characteristic of the mother

Number in

thousands Total

Months pregnant when prenatal care began

Less than

3 months

3–4

months

5 months or

more or no care

Percent distribution

All pregnancies ending in a live birth1 .......... 12,821 100.0 67.9 18.1 14.0

Education (at interview)2

Less than 12 years ..................... 1,877 100.0 49.1 19.2 31.6

12 years ............................ 4,277 100.0 68.2 21.5 10.3

13 years or more ...................... 5,514 100.0 79.4 12.3 8.4

Most recent occupation2

Professional or managerial ................ 2,620 100.0 80.5 13.4 6.1

Sales or clerical ....................... 4,845 100.0 71.8 16.9 11.2

Service ............................ 2,010 100.0 64.6 16.2 19.1

Farm, craft, or operative .................. 1,152 100.0 66.8 21.7 11.5

Never worked ........................ 1,040 100.0 53.7 20.0 26.3

Poverty level income (at interview)2

149 percent or less ..................... 2,649 100.0 52.8 20.1 27.2

150–299 percent ...................... 3,643 100.0 68.6 21.3 10.1

300 percent or more .................... 5,375 100.0 80.4 12.1 7.5

Medicaid for prenatal care or delivery

No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11,804 100.0 69.4 17.3 13.3

Yes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,018 100.0 50.0 27.7 22.2

Residence (at interview)

Metropolitan/central city .................. 2,244 100.0 67.4 17.7 15.0

Metropolitan/suburban ................... 7,271 100.0 71.3 15.8 12.9

Nonmetropolitan ....................... 3,307 100.0 60.7 23.5 15.9

1Includes births with missing data on first prenatal care visit.

2Limited to women 20–44 years at time of birth.

34
Table 6. Number of pregnancies ending in a live birth in January 1984 or later to black women 15–44 years of age and percent

distribution by months pregnant when prenatal care began, according to selected characteristics of the mother: United States, 1988

Characteristic of the mother

Number in

thousands Total

Months pregnant when prenatal care began

Less than

3 months

3–4

months

5 months or

more or no care

Percent distribution

All pregnancies ending in a live birth .......... 2,374 100.0 53.6 26.1 20.3

Education (at interview)1

Less than 12 years . . . . . . . . . . . . . . . . . . . . . 429 100.0 47.6 26.2 26.2

12 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714 100.0 53.2 31.2 15.6

13 years or more . . . . . . . . . . . . . . . . . . . . . . 655 100.0 72.8 18.8 8.4

Most recent occupation1

Professional or managerial . . . . . . . . . . . . . . . . 182 100.0 65.7 29.0 *5.3

Sales or clerical . . . . . . . . . . . . . . . . . . . . . . . 693 100.0 61.4 24.3 14.3

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356 100.0 60.2 26.3 13.5

Farm, craft, or operative . . . . . . . . . . . . . . . . . . 273 100.0 62.0 21.2 16.8

Never worked . . . . . . . . . . . . . . . . . . . . . . . . 294 100.0 45.0 29.1 26.0

Poverty level income (at interview)1

149 percent or less ..................... 1,005 100.0 54.1 27.5 18.4

150–299 percent . . . . . . . . . . . . . . . . . . . . . . 367 100.0 58.7 29.8 11.5

300 percent or more . . . . . . . . . . . . . . . . . . . . 426 100.0 70.7 17.0 12.3

Medicaid for prenatal care or delivery

No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,536 100.0 56.4 25.5 18.2

Yes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 838 100.0 48.5 27.2 24.3

Residence (at interview)

Metropolitan/central city .................. 1,237 100.0 51.9 25.8 22.3

Metropolitan/suburban . . . . . . . . . . . . . . . . . . . 742 100.0 61.5 24.0 14.5

Nonmetropolitan . . . . . . . . . . . . . . . . . . . . . . . 395 100.0 44.0 30.9 25.2

1Limited to women 20–44 years at time of birth.

35
Table 7. Number of pregnancies ending in live birth in January 1984 or later to women 15–44 years of age, percent receiving prenatal

care, and percent distribution of pregnancies receiving care by source of care for most prenatal visits, according to selected

characteristics of the birth: United States, 1988

Characteristic of the birth

Number in

thousands

Percent receiving

prenatal care Total

Source of most prenatal care

Private

doctor

Hospital

clinic

Other

clinic

Percent distribution

All pregnancies ending in a live birth1 .......... 16,220 98.7 100.0 69.1 10.6 20.3

Mother’s age at time of birth

Under 20 years ....................... 1,823 99.1 100.0 41.9 18.7 39.4

20–24 years ......................... 4,562 97.8 100.0 64.8 12.8 22.4

25–29 years ......................... 5,627 99.5 100.0 75.6 7.8 16.6

30–44 years ......................... 4,208 98.6 100.0 76.9 8.4 14.8

Birth order

First .............................. 4,881 99.4 100.0 66.8 10.8 22.3

Second ............................ 4,856 98.7 100.0 74.5 8.3 17.1

Third or higher ........................ 6,482 98.3 100.0 66.8 12.1 21.1

Mode of delivery

Cesarean section ...................... 3,789 99.3 100.0 73.6 10.2 16.2

Vaginal ............................ 12,379 98.5 100.0 67.7 10.7 21.5

Mother’s marital status at time of birth

Never married ........................ 2,695 97.9 100.0 46.3 23.2 30.4

Ever married ......................... 13,526 98.9 100.0 73.7 8.1 18.3

Wantedness status at conception

Intended ............................ 9,711 99.0 100.0 73.7 8.8 17.5

Mistimed ........................... 4,487 98.4 100.0 64.1 12.2 23.7

Unwanted ........................... 1,987 98.0 100.0 58.1 15.9 26.0

Timing of first prenatal visit

Within first trimester ..................... 11,919 100.0 100.0 73.0 8.9 18.2

After first trimester or never ................ 4,292 95.2 100.0 57.8 15.6 26.6

1Includes births with missing data on prenatal care, mode of delivery, or wantedness status.

36
Table 8. Number of pregnancies ending in live birth in January 1984 or later to white women 15–44 years of age, percent receiving

prenatal care, and percent distribution of pregnancies receiving care by source of care for most prenatal visits, according to selected

characteristics of the birth: United States, 1988

Characteristic of the birth

Number in

thousands

Percent receiving

prenatal care Total

Source of most prenatal care

Private

doctor

Hospital

clinic

Other

clinic

Percent distribution

All pregnancies ending in a live birth1 .......... 12,821 99.0 100.0 74.9 7.8 17.3

Mother’s age at time of birth

Under 20 years ....................... 1,144 100.0 100.0 44.3 15.3 40.4

20–24 years ......................... 3,476 97.8 100.0 71.2 9.8 19.0

25–29 years ......................... 4,726 99.4 100.0 80.5 5.5 14.0

30–44 years ......................... 3,474 99.2 100.0 80.8 6.4 12.7

Birth order

First .............................. 3,815 99.5 100.0 72.4 7.6 19.9

Second ............................ 3,899 99.3 100.0 80.7 6.1 13.2

Third or higher ........................ 5,107 98.4 100.0 72.2 9.2 18.6

Mode of delivery

Cesarean section ...................... 2,965 99.8 100.0 77.7 8.0 14.3

Vaginal ............................ 9,809 98.8 100.0 74.0 7.7 18.2

Mother’s marital status at time of birth

Never married ........................ 1,220 98.1 100.0 57.6 16.3 26.1

Ever married ......................... 11,601 99.1 100.0 76.7 6.9 16.4

Wantedness status at conception

Intended ............................ 8,056 99.4 100.0 77.9 6.8 15.4

Mistimed ........................... 3,546 98.1 100.0 69.6 9.7 20.7

Unwanted ........................... 1,193 98.6 100.0 70.3 9.4 20.4

Timing of first prenatal visit

Within first trimester ..................... 9,692 100.0 100.0 78.1 6.4 15.5

After first trimester or never ................ 3,120 95.9 100.0 64.5 12.2 23.3

1Includes births with missing data on prenatal care, mode of delivery, or wantedness status.

37
Table 9. Number of pregnancies ending in live birth in January 1984 or later to black women 15–44 years of age, percent receiving

prenatal care, and percent distribution of pregnancies receiving care by source of prenatal care for most visits, according to selected

characteristics of the birth: United States, 1988

Characteristic of the birth

Number in

thousands

Percent receiving

prenatal care Total

Source of most prenatal care

Private

doctor

Hospital

clinic

Other

clinic

Percent distribution

All pregnancies ending in a live birth1 .......... 2,374 97.9 100.0 45.5 23.6 30.9

Mother’s age at time of birth

Under 20 years . . . . . . . . . . . . . . . . . . . . . . . 576 97.0 100.0 36.5 23.4 40.1

20–24 years . . . . . . . . . . . . . . . . . . . . . . . . . 777 96.6 100.0 47.1 26.2 26.8

25–29 years . . . . . . . . . . . . . . . . . . . . . . . . . 587 99.4 100.0 46.9 21.0 32.2

30–44 years . . . . . . . . . . . . . . . . . . . . . . . . . 434 99.5 100.0 53.1 22.9 24.0

Birth order

First . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 719 98.5 100.0 43.6 24.6 31.8

Second . . . . . . . . . . . . . . . . . . . . . . . . . . . . 641 97.4 100.0 50.8 18.4 30.8

Third or higher ........................ 1,014 97.8 100.0 43.5 26.3 30.2

Mode of delivery

Cesarean section . . . . . . . . . . . . . . . . . . . . . . 555 96.3 100.0 54.5 21.9 23.6

Vaginal ............................ 1,814 98.4 100.0 42.9 24.0 33.1

Mother’s marital status at time of birth

Never married ........................ 1,323 97.4 100.0 38.3 27.9 33.8

Ever married ......................... 1,051 98.6 100.0 54.7 18.1 27.2

Wantedness status at conception

Intended . . . . . . . . . . . . . . . . . . . . . . . . . . . . 961 97.8 100.0 50.4 23.3 26.2

Mistimed . . . . . . . . . . . . . . . . . . . . . . . . . . . 729 99.5 100.0 46.1 22.5 31.4

Unwanted . . . . . . . . . . . . . . . . . . . . . . . . . . . 674 96.4 100.0 37.6 25.1 37.3

Timing of first prenatal visit

Within first trimester ..................... 1,537 100.0 100.0 47.7 23.7 28.6

After first trimester or never . . . . . . . . . . . . . . . . 837 94.1 100.0 41.2 23.5 35.3

1Includes births with missing data on source of prenatal care, mode of delivery, or wantedness status.

38
Table 10. Number of pregnancies ending in a live birth in January 1984 or later to women 15–44 years of age, percent receiving prenatal

care, and percent distribution of pregnancies receiving care by source of care for most prenatal visits, according to selected

characteristics of the mother: United States, 1988

Characteristic of the mother

Number in

thousands

Percent receiving

prenatal care Total

Source of most prenatal care

Private

doctor

Hospital

clinic

Other

clinic

Percent distribution

All pregnancies ending in a live birth .......... 16,220 98.7 100.0 69.1 10.6 20.3

Race and ethnicity

Hispanic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,115 96.5 100.0 53.3 15.1 31.5

Non-Hispanic white ..................... 11,025 99.5 100.0 77.9 7.0 15.1

Non-Hispanic black ..................... 2,287 97.8 100.0 45.3 23.4 31.3

Non-Hispanic other . . . . . . . . . . . . . . . . . . . . . 794 96.3 100.0 55.3 *12.4 *32.3

Education (at interview)1

Less than 12 years ..................... 2,557 94.9 100.0 50.4 17.4 32.2

12 years ............................ 5,287 99.3 100.0 73.4 9.5 17.1

13 years or more ...................... 6,554 99.7 100.0 80.1 6.6 13.2

Most recent occupation1

Professional or managerial ................ 2,928 100.0 100.0 83.9 *3.8 12.3

Sales or clerical ....................... 5,921 98.9 100.0 77.3 8.2 14.5

Service ............................ 2,495 99.2 100.0 67.7 9.2 23.1

Farm, craft, or operative .................. 1,539 98.9 100.0 65.3 13.3 21.3

Never worked ........................ 1,515 93.9 100.0 46.1 23.4 30.4

Poverty level income (at interview)1

149 percent or less ..................... 3,908 95.9 100.0 53.1 17.3 29.6

150–299 percent ...................... 4,331 99.3 100.0 76.4 8.3 15.3

300 percent or more .................... 6,158 100.0 100.0 81.7 5.7 12.6

Medicaid for prenatal care or delivery

No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14,256 98.7 100.0 74.6 8.3 17.1

Yes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,964 98.7 100.0 29.8 26.9 43.3

Residence (at interview)

Metropolitan/central city .................. 3,764 98.9 100.0 55.9 18.8 25.3

Metropolitan/suburban ................... 8,630 99.1 100.0 73.2 7.9 18.8

Nonmetropolitan ....................... 3,827 97.6 100.0 72.9 8.4 18.7

1Limited to women 20–44 years at time of birth.

39
Table 11. Number of pregnancies ending in a live birth in January 1984 or later to white women 15–44 years of age, percent receiving

prenatal care, and percent distribution of pregnancies receiving care by source of care for most prenatal visits, according to selected

characteristics of the mother: United States, 1988

Characteristic of the mother

Number in

thousands

Percent receiving

prenatal care Total

Source of most prenatal care

Private

doctor

Hospital

clinic

Other

clinic

Percent distribution

All pregnancies ending in a live birth .......... 12,821 99.0 100.0 74.9 7.8 17.3

Education (at interview)1

Less than 12 years ..................... 1,877 95.1 100.0 56.0 13.3 30.7

12 years ............................ 4,277 99.7 100.0 79.5 7.4 13.1

13 years or more ...................... 5,514 99.6 100.0 83.7 4.8 11.5

Most recent occupation1

Professional or managerial ................ 2,620 100.0 100.0 84.9 *3.3 11.9

Sales or clerical ....................... 4,845 99.3 100.0 81.8 6.4 11.9

Service ............................ 2,010 99.2 100.0 74.8 6.8 18.4

Farm, craft, or operative .................. 1,152 98.8 100.0 72.4 11.8 15.8

Never worked ........................ 1,040 93.8 100.0 52.5 *15.5 32.0

Poverty level income (at interview)1

149 percent or less ..................... 2,649 95.9 100.0 60.5 12.7 26.9

150–299 percent ...................... 3,642 99.4 100.0 80.9 7.0 12.1

300 percent or more .................... 5,375 100.0 100.0 84.1 4.4 11.5

Medicaid for prenatal care or delivery

No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11,804 99.0 100.0 78.5 6.8 14.8

Yes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,018 99.0 100.0 33.7 19.4 46.9

Residence (at interview)

Metropolitan/central city .................. 2,244 100.0 100.0 64.9 11.9 23.2

Metropolitan/suburban ................... 7,271 99.3 100.0 77.0 6.6 16.3

Nonmetropolitan ....................... 3,307 97.6 100.0 77.0 7.4 15.6

1Limited to women 20–44 years at time of birth.

40
Table 12. Number of pregnancies ending in a live birth in January 1984 or later to black women 15–44 years of age, percent receiving

prenatal care, and percent distribution of pregnancies receiving care by source of care for most prenatal visits, according to selected

characteristics of the mother: United States, 1988

Characteristic of the mother

Number in

thousands

Percent receiving

prenatal care Total

Source of most prenatal care

Private

doctor

Hospital

clinic

Other

clinic

Percent distribution

All pregnancies ending in a live birth .......... 2,374 97.9 100.0 45.5 23.6 30.9

Education (at interview)1

Less than 12 years . . . . . . . . . . . . . . . . . . . . . 429 97.5 100.0 29.7 33.1 37.2

12 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714 97.0 100.0 50.0 21.0 29.0

13 years or more . . . . . . . . . . . . . . . . . . . . . . 655 100.0 100.0 58.8 20.4 20.8

Most recent occupation1

Professional or managerial . . . . . . . . . . . . . . . . 182 100.0 100.0 63.4 *14.5 22.1

Sales or clerical . . . . . . . . . . . . . . . . . . . . . . . 693 96.9 100.0 57.4 22.9 19.7

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356 99.3 100.0 37.2 23.9 39.0

Farm, craft, or operative . . . . . . . . . . . . . . . . . . 273 99.3 100.0 44.6 22.7 32.7

Never worked . . . . . . . . . . . . . . . . . . . . . . . . 294 97.9 100.0 35.8 31.6 32.6

Poverty level income (at interview)1

149 percent or less ..................... 1,005 96.8 100.0 39.7 27.5 32.8

150–299 percent . . . . . . . . . . . . . . . . . . . . . . 367 100.0 100.0 51.4 20.4 28.2

300 percent or more . . . . . . . . . . . . . . . . . . . . 426 100.0 100.0 66.2 17.5 16.3

Medicaid for prenatal care or delivery

No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,536 97.8 100.0 55.3 17.7 27.0

Yes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 838 98.2 100.0 27.9 34.3 37.8

Residence (at interview)

Metropolitan/central city .................. 1,237 97.3 100.0 42.5 27.2 30.3

Metropolitan/suburban . . . . . . . . . . . . . . . . . . . 742 99.6 100.0 51.0 23.4 25.7

Nonmetropolitan . . . . . . . . . . . . . . . . . . . . . . . 395 96.5 100.0 44.5 *12.7 42.8

1Limited to women 20–44 years at time of birth.

41
Table 13. Number of women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and percent

distribution by average number of cigarettes smoked per day during the pregnancy, according to selected characteristics of the

pregnancy: United States, 1988

Characteristic of the pregnancy

Number of

women in

thousands Total

Average number of cigarettes smoked

per day during pregnancy

None

Fewer

than 15

15 or

more

Percent distribution

All women1 .......................... 32,465 100.0 72.5 16.5 11.0

Mother’s age at pregnancy outcome

Under 20 years ....................... 2,966 100.0 67.8 18.3 13.9

20–24 years ......................... 9,718 100.0 66.7 19.6 13.8

25–29 years ......................... 11,657 100.0 72.7 16.7 10.6

30–44 years ......................... 8,123 100.0 80.9 11.8 7.3

Pregnancy order

First .............................. 7,660 100.0 74.3 16.6 9.1

Second ............................ 10,812 100.0 75.3 15.0 9.6

Third or higher ........................ 13,992 100.0 69.3 17.5 13.2

Year of pregnancy outcome

1985–1988 .......................... 11,661 100.0 76.6 15.7 7.6

1981–1984 .......................... 7,960 100.0 74.1 14.3 11.6

1980 or earlier ........................ 12,844 100.0 67.8 18.5 13.7

Mother’s marital status at pregnancy outcome

Never married ........................ 4,468 100.0 66.3 24.3 9.4

Ever married ......................... 27,997 100.0 73.5 15.2 11.3

Wantedness status at conception

Intended ............................ 19,437 100.0 75.7 15.0 9.4

Mistimed ........................... 8,011 100.0 69.0 19.2 11.8

Unwanted ........................... 4,960 100.0 65.7 18.1 16.1

Pregnancy outcome

Live birth ........................... 28,955 100.0 73.0 15.9 11.1

Spontaneous pregnancy loss ............... 3,510 100.0 68.4 20.9 10.7

Timing of first prenatal visit2

Within first trimester ..................... 9,230 100.0 77.3 14.1 8.6

After first trimester or never ................ 3,100 100.0 72.6 17.4 10.0

1Includes women with missing data on smoking during pregnancy, wantedness status, or first prenatal care visit.

2Prenatal care items only pertain to live births in or after January 1984.

42
Table 14. Number of white women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and percent

distribution by average number of cigarettes smoked per day during the pregnancy, according to selected characteristics of the

pregnancy: United States, 1988

Characteristic of the pregnancy

Number of

women in

thousands Total

Average number of cigarettes smoked

per day during pregnancy

None

Fewer

than 15

15 or

more

Percent distribution

All women1 .......................... 26,195 100.0 71.3 16.3 12.4

Mother’s age at pregnancy outcome

Under 20 years ....................... 1,985 100.0 60.8 20.1 19.1

20–24 years ......................... 7,642 100.0 65.5 18.8 15.7

25–29 years ......................... 9,899 100.0 71.5 16.7 11.8

30–44 years ......................... 6,669 100.0 80.9 11.7 7.4

Pregnancy order

First .............................. 5,978 100.0 72.0 17.3 10.7

Second ............................ 8,922 100.0 73.9 15.0 11.1

Third or higher ........................ 11,295 100.0 68.9 16.8 14.3

Year of pregnancy outcome

1985–1988 .......................... 9,203 100.0 75.2 16.1 8.7

1981–1984 .......................... 6,401 100.0 73.8 13.2 13.0

1980 or earlier ........................ 10,590 100.0 66.4 18.3 15.2

Mother’s marital status at pregnancy outcome

Never married ........................ 2,131 100.0 58.5 26.4 15.0

Ever married ......................... 24,064 100.0 72.4 15.4 12.2

Wantedness status at conception

Intended ............................ 16,395 100.0 74.9 14.9 10.2

Mistimed ........................... 6,352 100.0 66.9 19.2 13.9

Unwanted ........................... 3,407 100.0 62.2 17.9 19.8

Pregnancy outcome

Live birth ........................... 23,411 100.0 71.7 15.8 12.5

Spontaneous pregnancy loss ............... 2,784 100.0 67.9 20.8 11.3

Timing of first prenatal visit2

Within first trimester ..................... 7,509 100.0 76.4 14.2 9.4

After first trimester or never ................ 2,242 100.0 68.6 18.8 12.7

1Includes women with missing data on smoking during pregnancy, wantedness status, and first prenatal care visit.

2Prenatal care items only pertain to live births in or after January 1984.

43
Table 15. Number of black women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and percent

distribution by average number of cigarettes smoked per day during the pregnancy, according to selected characteristics of the

pregnancy: United States, 1988

Characteristic of the pregnancy

Number of

women in

thousands Total

Average number of cigarettes smoked

per day during pregnancy

None

Fewer

than 15

15 or

more

Percent distribution

All women1 .......................... 4,734 100.0 76.6 17.8 5.6

Mother’s age at pregnancy outcome

Under 20 years . . . . . . . . . . . . . . . . . . . . . . . 859 100.0 82.7 13.3 *3.9

20–24 years ......................... 1,651 100.0 71.8 22.4 5.8

25–29 years ......................... 1,342 100.0 78.1 17.3 4.6

30–44 years . . . . . . . . . . . . . . . . . . . . . . . . . 881 100.0 77.3 14.1 8.6

Pregnancy order

First .............................. 1,286 100.0 82.4 13.5 4.0

Second ............................ 1,376 100.0 82.4 15.0 *2.6

Third or higher ........................ 2,072 100.0 69.2 22.2 8.6

Year of pregnancy outcome

1985–1988 .......................... 1,710 100.0 79.9 15.1 5.0

1981–1984 .......................... 1,169 100.0 74.4 20.8 4.8

1980 or earlier ........................ 1,855 100.0 75.0 18.3 6.7

Mother’s marital status at pregnancy outcome

Never married ........................ 2,091 100.0 75.0 20.5 4.5

Ever married ......................... 2,642 100.0 77.9 15.6 6.5

Wantedness status at conception

Intended ............................ 2,048 100.0 78.5 16.6 4.9

Mistimed ........................... 1,340 100.0 79.2 16.5 4.3

Unwanted ........................... 1,330 100.0 71.0 21.0 8.0

Pregnancy outcome

Live birth ........................... 4,204 100.0 76.8 17.8 5.4

Spontaneous pregnancy loss . . . . . . . . . . . . . . . 530 100.0 75.1 17.5 *7.4

Timing of first prenatal visit2

Within first trimester ..................... 1,217 100.0 78.9 16.6 4.5

After first trimester or never . . . . . . . . . . . . . . . . 600 100.0 82.6 13.1 *4.3

1Includes women with missing data on smoking during pregnancy, wantedness status, or first prenatal care visit.

2Prenatal care items only pertain to live births in or after January 1984.

44
Table 16. Number of women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and percent

distribution by average number of cigarettes smoked per day during the pregnancy, according to selected characteristics of the mother:

United States, 1988

Characteristic of the mother

Number of

women in

thousands Total

Average number of cigarettes smoked

per day during pregnancy

None

Fewer

than 15

15 or

more

Percent distribution

All women1 .......................... 32,465 100.0 72.5 16.5 11.0

Race and ethnicity

Hispanic ............................ 3,402 100.0 86.3 12.5 *1.2

Non-Hispanic white ..................... 23,419 100.0 69.5 16.8 13.7

Non-Hispanic black ..................... 4,545 100.0 76.6 17.5 5.9

Non-Hispanic other ..................... 1,098 100.0 76.3 17.2 *6.5

Education (at interview)2

Less than 12 years ..................... 5,231 100.0 57.0 25.0 18.0

12 years ............................ 11,663 100.0 70.9 16.2 12.8

13 years or more ...................... 12,604 100.0 81.5 12.7 5.8

Most recent occupation2

Professional or managerial ................ 6,597 100.0 81.2 11.2 7.6

Sales or clerical ....................... 11,955 100.0 74.0 15.7 10.3

Service ............................ 5,371 100.0 66.3 20.0 13.7

Farm, craft, or operative .................. 3,737 100.0 63.9 19.8 16.3

Never worked ........................ 1,839 100.0 74.6 20.3 5.1

Poverty level income (at interview)2

149 percent or less ..................... 6,681 100.0 66.1 21.5 12.4

150–299 percent ...................... 8,201 100.0 74.1 14.9 11.1

300 percent or more .................... 14,616 100.0 75.5 14.7 9.8

Residence (at interview)

Metropolitan/central city .................. 7,096 100.0 72.2 18.3 9.5

Metropolitan/suburban ................... 17,229 100.0 73.4 15.8 10.8

Nonmetropolitan ....................... 8,140 100.0 70.8 16.3 12.9

1Includes women with missing data on smoking during pregnancy.

2Limited to women 20–44 years at time of pregnancy outcome.

45
Table 17. Number of white women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and percent

distribution by average number of cigarettes smoked per day during the pregnancy, according to selected characteristics of the mother:

United States, 1988

Characteristic of the mother

Number of

women in

thousands Total

Average number of cigarettes smoked

per day during pregnancy

None

Fewer

than 15

15 or

more

Percent distribution

All women1 .......................... 26,195 100.0 71.3 16.3 12.4

Education (at interview)2

Less than 12 years ..................... 3,933 100.0 54.8 24.4 20.8

12 years ............................ 9,736 100.0 69.6 16.3 14.1

13 years or more ...................... 10,542 100.0 81.1 12.6 6.4

Most recent occupation2

Professional or managerial ................ 5,861 100.0 80.0 11.7 8.3

Sales or clerical ....................... 10,055 100.0 73.1 15.9 11.0

Service ............................ 4,138 100.0 64.4 19.8 15.8

Farm, craft, or operative .................. 2,899 100.0 62.5 18.2 19.3

Never worked ........................ 1,257 100.0 76.0 19.5 *4.5

Poverty level income (at interview)2

149 percent or less ..................... 4,491 100.0 64.6 20.4 14.9

150–299 percent ...................... 6,910 100.0 72.6 15.3 12.0

300 percent or more .................... 12,809 100.0 74.6 14.8 10.6

Residence (at interview)

Metropolitan/central city .................. 4,453 100.0 71.0 17.7 11.3

Metropolitan/suburban ................... 14,659 100.0 72.2 15.9 12.0

Nonmetropolitan ....................... 7,083 100.0 69.8 16.3 13.9

1Includes women with missing data on smoking during pregnancy.

2Limited to women 20–44 years at time of pregnancy outcome.

46
Table 18. Number of black women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and percent

distribution by average number of cigarettes smoked per day during the pregnancy, according to selected characteristics of the mother:

United States, 1988

Characteristic of the mother

Number of

women in

thousands Total

Average number of cigarettes smoked

per day during pregnancy

None

Fewer

than 15

15 or

more

Percent distribution

All women1 .......................... 4,735 100.0 76.6 17.8 5.6

Education (at interview)2

Less than 12 years . . . . . . . . . . . . . . . . . . . . . 900 100.0 60.5 29.4 10.1

12 years ............................ 1,564 100.0 78.9 15.8 5.3

13 years or more ...................... 1,410 100.0 80.7 15.2 4.2

Most recent occupation2

Professional or managerial . . . . . . . . . . . . . . . . 504 100.0 86.1 10.4 *3.5

Sales or clerical ....................... 1,398 100.0 78.1 16.1 5.8

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . 965 100.0 73.3 20.4 6.3

Farm, craft, or operative . . . . . . . . . . . . . . . . . . 635 100.0 70.0 24.6 5.5

Never worked . . . . . . . . . . . . . . . . . . . . . . . . 372 100.0 64.0 25.8 *10.2

Poverty level income (at interview)2

149 percent or less ..................... 1,763 100.0 67.7 24.9 7.4

150–299 percent . . . . . . . . . . . . . . . . . . . . . . 925 100.0 82.1 14.0 4.0

300 percent or more .................... 1,186 100.0 81.2 13.3 5.5

Residence (at interview)

Metropolitan/central city .................. 2,255 100.0 73.5 19.7 6.7

Metropolitan/suburban ................... 1,605 100.0 78.0 16.7 5.4

Nonmetropolitan . . . . . . . . . . . . . . . . . . . . . . . 874 100.0 82.0 14.7 *3.3

1Includes women with missing data on smoking during pregnancy.

2Limited to women 20–44 years at pregnancy outcome.

47
Table 19. Number of women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and percent

distribution by average frequency of alcoholic beverage consumption during the pregnancy, according to selected characteristics of the

pregnancy: United States, 1988

Characteristic of the pregnancy

Number of

women in

thousands Total

Average frequency of alcoholic beverage

consumption during pregnancy

None Subtotal

Less than

once a month

Once a

month

More than

once/month

Percent distribution

All women1 .......................... 32,465 100.0 66.5 33.5 18.8 6.3 8.4

Mother’s age at pregnancy outcome

Under 20 years ....................... 2,966 100.0 77.9 22.1 11.3 4.9 5.9

20–24 years ......................... 9,718 100.0 68.0 32.0 18.2 6.3 7.5

25–29 years ......................... 11,657 100.0 64.6 35.4 19.8 6.3 9.3

30–44 years ......................... 8,123 100.0 63.4 36.6 20.8 6.7 9.1

Pregnancy order

First .............................. 7,660 100.0 70.2 29.8 17.4 5.7 6.7

Second ............................ 10,812 100.0 66.8 33.2 18.9 6.1 8.2

Third or higher ........................ 13,992 100.0 64.3 35.7 19.5 6.7 9.4

Year of pregnancy outcome

1985–1988 .......................... 11,661 100.0 69.3 30.7 18.4 5.3 7.0

1981–1984 .......................... 7,960 100.0 67.6 32.4 18.4 5.6 8.4

1980 or earlier ........................ 12,844 100.0 63.3 36.7 19.5 7.6 9.6

Mother’s marital status at pregnancy outcome

Never married ........................ 4,468 100.0 71.6 28.4 11.1 6.3 10.9

Ever married ......................... 27,997 100.0 65.7 34.3 20.0 6.3 8.0

Wantedness status at conception

Intended ............................ 19,437 100.0 66.9 33.1 19.4 6.1 7.5

Mistimed ........................... 8,011 100.0 65.1 34.9 18.3 6.6 9.9

Unwanted ........................... 4,960 100.0 67.5 32.5 16.9 6.2 9.4

Pregnancy outcome

Live birth ........................... 28,955 100.0 66.5 33.5 19.6 6.4 7.5

Spontaneous pregnancy loss ............... 3,510 100.0 66.8 33.2 12.4 5.0 15.8

Timing of first prenatal visit2

Within first trimester ..................... 9,230 100.0 68.8 31.2 20.1 5.6 5.6

After first trimester or never ................ 3,100 100.0 70.6 29.4 18.0 5.1 6.2

1Includes women with missing data on drinking during pregnancy, wantedness status, or first prenatal care visit.

2Prenatal care items only pertain to live births in or after January 1984.

48
Table 20. Number of women 15–44 years of age whose most recent pregnancy ended in live birth or spontaneous loss and percent

distribution by average frequency of alcoholic beverage consumption during the pregnancy, according to selected characteristics of the

mother: United States, 1988

Characteristic of the mother

Number of

women in

thousands Total

Average frequency of alcoholic beverage

consumption during pregnancy

Never Subtotal

Less than

once a month

Once a

month

More than

once/month

Percent distribution

All women1 .......................... 32,465 100.0 66.5 33.5 18.8 6.3 8.4

Race and ethnicity

Hispanic ............................ 3,402 100.0 75.6 24.4 13.4 5.6 5.5

Non-Hispanic white ..................... 23,419 100.0 63.3 36.7 21.3 6.5 8.8

Non-Hispanic black ..................... 4,545 100.0 74.7 25.3 11.0 5.4 8.9

Non-Hispanic other ..................... 1,098 100.0 73.4 26.6 *14.1 *6.0 *6.5

Education (at interview)2

Less than 12 years ..................... 5,212 100.0 74.1 25.9 12.3 4.3 9.3

12 years ............................ 11,624 100.0 68.2 31.8 19.5 5.9 6.4

13 years or more ...................... 12,560 100.0 59.2 40.8 22.7 7.8 10.4

Most recent occupation2

Professional or managerial ................ 6,597 100.0 57.9 42.1 23.5 7.9 10.8

Sales or clerical ....................... 11,955 100.0 63.9 36.1 20.9 6.6 8.5

Service ............................ 5,371 100.0 69.2 30.8 18.4 4.3 8.0

Farm, craft, or operative .................. 3,737 100.0 70.8 29.2 13.7 7.8 7.7

Never worked ........................ 1,839 100.0 79.6 20.4 12.0 *3.2 5.2

Poverty level income (at interview)2

149 percent or less ..................... 6,655 100.0 72.5 27.5 13.9 4.4 9.1

150–299 percent ...................... 8,164 100.0 69.5 30.5 17.7 6.1 6.7

300 percent or more .................... 14,577 100.0 59.8 40.2 23.2 7.5 9.5

Residence (at interview)

Metropolitan/central city .................. 7,096 100.0 65.7 34.3 16.1 6.8 11.3

Metropolitan/suburban ................... 17,229 100.0 64.4 35.6 21.0 6.3 8.3

Nonmetropolitan ....................... 8,140 100.0 71.8 28.2 16.5 5.7 6.0

1Includes women with missing data on drinking during pregnancy.

2Limited to women 20–44 years at time of pregnancy outcome.

49
Table 21. Number of single live births to women 15–44 years of age and percent low birthweight, by race and selected characteristics of

the birth: United States, 1988

Characteristic of the birth

All races1 White Black

Number of

births in

thousands

Percent

low birthweight

Number of

births in

thousands

Percent

low birthweight

Number of

births in

thousands

Percent

low birthweight

All single live births2 .................... 69,472 7.4 55,437 6.1 10,670 14.2

Mother’s age at birth

Less than 20 years ..................... 13,839 10.3 9,395 8.3 3,846 15.3

20–24 years ......................... 26,644 7.6 21,581 6.2 3,923 14.4

25–44 years ......................... 28,990 5.8 24,461 5.1 2,901 12.4

Birth order

First .............................. 27,420 7.7 21,879 6.5 4,184 13.8

Second ............................ 21,090 6.5 17,125 5.3 2,944 12.8

Third or higher ........................ 20,962 7.9 16,432 6.3 3,543 15.9

Mode of delivery

Cesarean section ...................... 9,813 7.6 7,737 6.1 1,436 15.9

Vaginal ............................ 59,471 7.4 47,581 6.1 9,168 13.9

Sex of baby

Male .............................. 36,179 6.7 28,869 5.9 5,482 10.9

Female ............................ 33,234 8.1 26,515 6.1 5,183 17.7

Year of birth

1985–1988 .......................... 11,950 6.2 9,417 5.3 1,806 12.4

1981–1984 .......................... 15,245 5.8 12,168 4.3 2,127 13.3

1980 or earlier ........................ 42,277 8.3 33,852 6.9 6,737 14.9

Mother’s marital status at time of birth

Never married ........................ 10,073 10.8 4,272 6.1 5,292 14.3

Ever married ......................... 59,399 6.8 51,165 6.1 5,379 14.1

Wantedness status at conception

Intended ............................ 41,642 6.5 35,358 5.8 4,123 12.7

Mistimed ........................... 20,233 8.5 15,595 6.8 3,766 15.0

Unwanted ........................... 7,502 9.2 4,418 5.4 2,752 15.1

Timing of first prenatal visit3

Within first trimester ..................... 11,740 6.2 9,552 4.3 1,511 13.4

Later or never had prenatal care ............. 4,278 7.1 3,115 5.6 829 12.3

Site of most prenatal care3

Private doctor ........................ 10,794 5.0 9,283 4.3 1,033 11.0

Hospital clinic ........................ 1,655 9.6 970 *8.1 531 13.5

Other clinic .......................... 3,196 6.9 2,169 4.9 700 14.2

Payment for prenatal care3,4

Self, family, or friends ................... 7,326 4.6 6,285 4.1 664 *10.0

Private insurance ...................... 10,108 4.5 8,605 3.9 881 11.1

Medicaid/other government ................ 3,061 10.7 1,756 8.6 1,102 14.1

All other methods . . . . . . . . . . . . . . . . . . . . . . 437 *7.9 359 *6.9 51 *8.6

Smoking during pregnancy (if most recent)

Did not smoke ........................ 20,871 4.7 16,599 3.6 3,172 10.6

Fewer than 15 cigarettes per day ............ 4,550 10.6 3,645 8.1 728 22.4

15 or more cigarettes per day .............. 3,169 9.7 2,894 9.0 225 20.5

1Includes white, black, and other races; other races not shown separately.

2Includes births with missing data on delivery, sex, wantedness status, prenatal care, or smoking during pregnancy.

3Limited to births occurring in January 1984 or later.

4Women could choose all applicable methods of payment, so numbers may exceed total births.

50
Table 22. Number of single live births to women 15–44 years of age and percent low birthweight, by race and selected characteristics of

the mother: United States, 1988

Characteristic of the mother

All races1 White Black

Number of

births in

thousands

Percent

low birthweight

Number of

births in

thousands

Percent

low birthweight

Number of

births in

thousands

Percent

low birthweight

All single live births ..................... 69,472 7.4 55,437 6.1 10,670 14.2

Race and ethnicity

Hispanic ............................ 8,075 6.5 - - - - - - - - - - - -

Non-Hispanic white ..................... 48,726 6.2 - - - - - - - - - - - -

Non-Hispanic black ..................... 10,266 14.2 - - - - - - - - - - - -

Non-Hispanic other ..................... 2,405 *6.6 - - - - - - - - - - - -

Education (at interview)2

Less than 12 years ..................... 10,588 9.8 7,958 8.0 1,894 17.0

12 years ............................ 22,162 6.9 18,701 5.9 2,755 13.7

13 years or more ...................... 23,429 5.9 19,820 5.2 2,270 12.0

Most recent occupation2

Professional or managerial ................ 11,806 4.6 10,544 4.2 862 10.6

Sales or clerical ....................... 22,854 6.4 19,413 5.8 2,378 11.9

Service ............................ 10,765 8.4 8,370 6.7 1,802 15.4

Farm, craft, or operative .................. 7,148 9.3 5,639 7.8 1,123 16.5

Never worked ........................ 3,607 10.5 2,512 8.6 755 17.7

Poverty level income (at interview)2

149 percent or less ..................... 13,874 9.8 9,599 7.2 3,497 17.2

150–299 percent ...................... 16,659 5.9 14,223 5.4 1,632 11.1

300 percent or more .................... 25,647 6.3 22,657 5.8 1,790 10.5

Residence (at interview)

Metropolitan/central city .................. 14,793 9.3 8,885 7.1 5,039 13.7

Metropolitan/suburban ................... 36,458 6.6 30,948 5.6 3,501 14.2

Nonmetropolitan ....................... 18,222 7.4 15,604 6.5 2,130 15.3

1Includes white, black, and other races; other races not shown separately.

2Limited to women 20–44 years of age at time of birth.

51
Table 23. Number of single live births to women 15–44 years of age and percent low birthweight, according to year of birth and selected

characteristics of the birth: United States

Characteristic of the birth

1982 NSFG1 1988 NSFG1

1970 or before 1971–1980 1981–1984 1985–1988

Number in

thousands

Percent

low birthweightNumber in

thousands

Percent

low birthweightNumber in

thousands

Percent

low birthweightNumber in

thousands

Percent

low birthweight

All single live births2 .................... 29,652 16.2 33,132 9.2 15,245 5.8 11,950 6.2

Mother’s age at time of birth

Under 20 years ....................... 8,208 18.0 5,700 12.1 1,833 9.1 1,270 8.7

20–24 years ......................... 14,841 15.6 11,909 8.4 4,627 5.7 3,321 6.5

25–29 years ......................... 5,769 15.8 10,458 7.5 4,916 5.0 4,170 5.4

30–44 years . . . . . . . . . . . . . . . . . . . . . . . . . 829 13.7 5,064 11.3 3,869 5.3 3,189 6.0

Birth order

First .............................. 12,632 13.7 12,188 8.4 5,032 6.7 3,559 3.0

Second ............................ 8,337 14.4 9,854 7.4 4,575 5.2 3,581 5.0

Third or higher ........................ 8,683 21.7 11,089 11.6 5,638 5.4 4,810 7.1

Mother’s marital status at time of birth

Never married ........................ 2,630 31.7 4,563 16.1 2,152 8.9 2,031 10.2

Ever married ......................... 26,626 14.6 28,453 8.0 13,094 5.3 9,919 5.4

Wantedness status at conception

Intended ............................ 16,628 13.2 20,963 7.8 9,573 4.7 7,134 6.1

Mistimed ........................... 9,672 16.7 8,674 9.6 3,911 7.2 3,236 5.3

Unwanted ........................... 3,279 29.7 3,396 16.0 1,749 8.8 1,551 8.7

Smoking during pregnancy (if most recent)

Did not smoke ........................ 19,361 15.5 23,408 7.4 11,016 5.4 9,010 4.4

Less than 15 cigarettes a day .............. 4,813 17.7 4,669 13.2 2,087 7.8 1,780 11.6

More than 15 cigarettes a day .............. 5,346 17.3 4,915 13.8 1,589 6.4 947 10.6

1NSFG is National Survey of Family Growth.

2Totals based on 1982 NSFG include births with missing data on birthweight, age at delivery, marital status, wantedness, or smoking. Totals based on 1988 NSFG include births with missing data

on wantedness or smoking.

52
Table 24. Number of single live births to women 15–44 years of age and percent low birthweight, by year of birth and selected

characteristics of the mother: United States

Characteristic of the mother

1982 NSFG1 1988 NSFG1

1970 or before 1971–1980 1981–1984 1985–1988

Number in

thousands

Percent

low birthweightNumber in

thousands

Percent

low birthweightNumber in

thousands

Percent

low birthweightNumber in

thousands

Percent

low birthweight

All single live births2 .................... 29,652 16.2 33,132 9.2 15,245 5.8 11,950 6.2

Race and ethnicity

Hispanic ............................ 2,571 27.6 3,732 15.5 1,777 6.7 1,598 5.4

Non-Hispanic white ..................... 21,570 11.6 23,589 6.4 10,699 4.2 8,066 5.3

Non-Hispanic black ..................... 4,809 31.9 4,896 18.8 2,049 13.0 1,736 12.4

Education (at interview)3

Less than 12 years ..................... 4,904 29.1 5,112 15.7 2,234 8.7 2,008 8.4

12 years ............................ 9,820 9.7 11,326 8.1 4,912 5.3 3,828 6.1

13 years or more ...................... 6,644 14.4 10,993 5.8 6,266 4.2 4,843 4.8

Poverty level income (at interview)3

149 percent or less ..................... 4,537 18.9 7,413 12.2 3,566 6.9 2,978 9.1

150–299 percent ...................... 7,432 13.5 9,106 8.5 4,139 5.0 3,178 3.8

300 percent or more .................... 9,469 15.6 10,913 6.2 5,707 4.6 4,523 5.4

Residence (at interview)

Metropolitan/central city .................. 8,279 21.9 9,330 13.6 3,283 6.9 2,861 7.8

Metropolitan/suburban ................... 14,318 12.5 16,253 7.0 8,038 5.0 6,385 6.0

Nonmetropolitan ....................... 7,055 17.2 7,549 8.6 3,924 6.5 2,703 5.0

1NSFG is National Survey of Family Growth.

2Totals based on 1982 NSFG include births with missing data on race/ethnicity, education, income, or metropolitan residence.

3Limited to women 20–44 years of age at time of birth.

53
Table 25. Number of live birth deliveries in January 1984 or later to women 15–44 years of age and percent of delivery costs paid from

specified sources, by selected characteristics of the birth: United States, 1988

Characteristic of the birth

Number of

births in

thousands

Source of payment for delivery

Self,

family, or

friends

Private

medical

insurance Medicaid

Other

government

All

other

Percent1

All live births2 ........................ 16,220 44.0 65.7 11.0 9.3 2.5

Mother’s age at pregnancy outcome

Under 20 years ....................... 1,823 36.6 30.1 29.9 19.4 *2.3

20–24 years ......................... 4,562 42.0 53.0 15.4 12.4 3.8

25–29 years ......................... 5,627 44.5 75.4 6.8 7.2 *1.9

30–44 years ......................... 4,208 48.7 82.2 3.7 4.3 2.0

Pregnancy order

First .............................. 4,881 41.8 64.1 11.0 11.2 2.8

Second ............................ 4,856 48.1 72.9 10.1 6.2 1.6

Third or higher ........................ 6,482 42.5 61.5 13.3 10.1 2.9

Mode of delivery

Cesarean section ...................... 3,789 47.8 73.7 10.1 8.4 *1.6

Vaginal ............................ 12,379 42.8 63.3 11.4 9.6 2.8

Birthweight

Normal (2,500 grams or more) .............. 15,188 44.7 66.7 10.8 8.4 2.4

Low (less than 2,500 grams) ............... 1,032 33.9 53.5 14.6 22.5 *4.0

Mother’s marital status at pregnancy outcome

Never married ........................ 2,695 21.2 23.0 38.0 26.0 3.2

Ever married ......................... 13,526 48.5 74.2 5.7 5.9 2.4

Wantedness status at conception

Intended ............................ 9,711 47.4 74.1 6.8 6.7 2.5

Mistimed ........................... 4,487 40.6 56.6 15.7 11.5 2.8

Unwanted ........................... 1,987 34.5 45.1 21.2 17.1 *2.0

Timing of first prenatal visit

Within first trimester ..................... 10,958 44.8 72.6 8.4 7.4 2.1

After first trimester or never ................ 5,613 41.6 46.6 18.2 14.4 3.5

Site of most prenatal care

Private doctor ........................ 10,946 51.6 78.1 4.6 5.7 1.4

Hospital clinic ........................ 1,675 29.3 34.1 27.9 17.1 7.5

Other clinic .......................... 3,216 24.4 42.3 24.4 17.5 3.6

1The sum of the percents exceeds 100 because some women reported more than one source of payment for delivery.

2Includes births with missing data on source of payment, mode of delivery, wantedness, first prenatal care visit, or site of most prenatal care.

54
Table 26. Number of live birth deliveries in January 1984 or later to white women 15–44 years of age and percent of delivery costs paid

from specified sources, by selected characteristics of the birth: United States, 1988

Characteristic of the birth

Number of

births in

thousands

Source of payment for delivery

Self,

family, or

friends

Private

medical

insurance Medicaid

Other

government

All

other

Percent1

All live births2 ........................ 12,821 47.4 70.5 7.1 8.1 2.5

Mother’s age at pregnancy outcome

Under 20 years ....................... 1,144 43.0 37.1 *24.3 17.1 *2.2

20–24 years ......................... 3,476 47.6 55.2 11.0 12.1 4.1

25–29 years ......................... 4,726 46.2 79.3 *3.4 6.7 *1.8

30–44 years ......................... 3,474 50.3 84.7 *2.5 *2.9 *1.9

Pregnancy order

First .............................. 3,815 44.5 70.2 6.2 10.1 2.7

Second ............................ 3,899 52.2 77.5 5.1 4.5 *1.5

Third or higher ........................ 5,107 45.9 65.3 9.3 9.3 3.1

Mode of delivery

Cesarean section ...................... 2,965 50.2 78.6 *6.2 7.8 *1.6

Vaginal ............................ 9,809 46.6 68.0 7.4 8.2 2.8

Birthweight

Normal (2,500 grams or more) .............. 12,164 47.8 70.9 7.1 7.2 2.4

Low (less than 2,500 grams) . . . . . . . . . . . . . . . 657 40.7 61.8 *5.8 23.4 *4.7

Mother’s marital status at pregnancy outcome

Never married ........................ 1,220 26.9 26.6 30.3 29.2 *4.3

Ever married ......................... 11,601 49.6 75.1 4.6 5.8 2.3

Wantedness status at conception

Intended ............................ 8,056 49.9 76.9 4.3 6.1 2.4

Mistimed ........................... 3,546 43.9 61.3 11.9 9.7 *2.9

Unwanted ........................... 1,193 41.2 54.3 *11.2 16.5 *1.7

Timing of first prenatal visit

Within first trimester ..................... 8,695 47.5 77.0 5.1 6.5 2.1

After first trimester or never . . . . . . . . . . . . . . . . 4,117 47.1 50.4 13.2 12.9 *3.7

Site of most prenatal care

Private doctor ........................ 9,410 52.2 80.2 3.0 5.2 1.5

Hospital clinic . . . . . . . . . . . . . . . . . . . . . . . . 978 38.5 39.4 17.9 16.2 *9.6

Other clinic .......................... 2,179 28.8 44.4 20.2 16.9 *3.6

1The sum of the percents exceeds 100 because some women reported more than one source of payment for delivery.

2Includes births with missing data on source of payment, mode of delivery, wantedness, first prenatal care visit, or site of most prenatal care.

55
Table 27. Number of live birth deliveries in January 1984 or later to black women 15–44 years of age and percent of delivery costs paid

from specified sources, by selected characteristics of the birth: United States, 1988

Characteristic of the birth

Number of

births in

thousands

Source of payment for delivery

Self,

family, or

friends

Private

medical

insurance Medicaid

Other

government

All

other

Percent1

All live births2 ........................ 2,374 26.6 40.1 32.8 15.6 2.6

Mother’s age at pregnancy outcome

Under 20 years . . . . . . . . . . . . . . . . . . . . . . . 576 24.3 17.4 43.5 21.2 *2.0

20–24 years . . . . . . . . . . . . . . . . . . . . . . . . . 777 26.0 35.4 36.4 15.2 *3.2

25–29 years . . . . . . . . . . . . . . . . . . . . . . . . . 587 25.6 54.1 29.3 10.4 *2.5

30–44 years . . . . . . . . . . . . . . . . . . . . . . . . . 434 32.0 60.3 16.6 15.7 *2.2

Pregnancy order

First . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 719 26.6 35.5 35.3 16.0 *3.1

Second . . . . . . . . . . . . . . . . . . . . . . . . . . . . 641 29.0 43.5 29.7 13.9 *2.7

Third or higher ........................ 1,014 25.0 41.1 33.0 16.3 *2.1

Mode of delivery

Cesarean section . . . . . . . . . . . . . . . . . . . . . . 555 32.6 46.4 29.0 11.7 *2.0

Vaginal ............................ 1,814 24.7 38.2 34.0 16.7 2.7

Birthweight

Normal (2,500 grams or more) .............. 2,054 27.5 40.4 32.4 15.4 2.7

Low (less than 2,500 grams) . . . . . . . . . . . . . . . 320 20.8 37.6 35.1 *17.1 *1.6

Mother’s marital status at pregnancy outcome

Never married ........................ 1,323 17.7 19.2 46.4 21.8 *2.1

Ever married ......................... 1,051 37.7 66.2 15.7 7.8 *3.1

Wantedness status at conception

Intended . . . . . . . . . . . . . . . . . . . . . . . . . . . . 961 29.2 52.2 26.7 12.1 *2.6

Mistimed . . . . . . . . . . . . . . . . . . . . . . . . . . . 729 28.0 35.3 33.7 18.1 *2.2

Unwanted . . . . . . . . . . . . . . . . . . . . . . . . . . . 674 21.3 28.0 40.3 18.0 *2.9

Timing of first prenatal visit

Within first trimester ..................... 1,272 29.5 43.9 30.6 14.3 2.5

After first trimester or never ................ 1,102 21.3 32.9 36.8 17.9 *2.7

Site of most prenatal care

Private doctor ........................ 1,046 43.5 57.7 20.2 8.9 *0.6

Hospital clinic . . . . . . . . . . . . . . . . . . . . . . . . 542 12.2 25.5 47.0 16.0 *4.4

Other clinic . . . . . . . . . . . . . . . . . . . . . . . . . . 709 13.2 26.2 40.9 24.9 *3.6

1The sum of the percents exceeds 100 because some women reported more than one source of payment for delivery.

2Includes births with missing data on source of payment, mode of delivery, wantedness, first prenatal care visit, or site of most prenatal care.

56
Table 28. Number of live birth deliveries in January 1984 or later to women 15–44 years of age and percent of delivery costs paid from

specified sources, by selected characteristics of the mother: United States, 1988

Characteristic of the mother

Number of

births in

thousands

Source of payment for delivery

Self,

family, or

friends

Private

medical

insurance Medicaid

Other

government

All

other

Percent1

All live births2 ........................ 16,220 44.0 65.7 11.0 9.3 2.5

Race and ethnicity

Hispanic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,115 47.1 41.4 20.6 12.8 *0.9

Non-Hispanic white ..................... 11,025 47.0 75.2 5.0 7.4 2.7

Non-Hispanic black ..................... 2,287 26.8 39.9 32.6 15.8 2.5

Non-Hispanic other . . . . . . . . . . . . . . . . . . . . . 794 42.8 73.0 *6.7 *6.5 *3.5

Education (at interview)3

Less than 12 years ..................... 2,556 41.7 32.3 21.0 21.5 *3.1

12 years ............................ 5,287 44.5 72.4 8.5 7.3 2.7

13 years or more ...................... 6,554 46.5 83.3 3.9 3.3 2.2

Most recent occupation3

Professional or managerial ................ 2,928 44.9 90.8 *1.3 *1.5 *1.2

Technical, sales, or administrative ............ 5,921 48.5 78.3 4.3 5.2 2.2

Service ............................ 2,495 44.1 58.0 12.9 12.4 *3.6

Farm, craft, or operative .................. 1,539 33.2 58.2 15.3 14.6 *3.8

Never worked ........................ 1,515 44.3 31.8 26.1 17.4 *3.4

Poverty level income (at interview)3

149 percent or less ..................... 3,908 38.5 31.2 24.4 21.7 4.6

150–299 percent ...................... 4,331 48.6 78.9 4.7 3.8 *2.3

300 percent or more .................... 6,158 46.4 88.8 *1.5 2.3 1.4

Residence (at interview)

Metropolitan/central city .................. 3,764 32.7 50.0 21.0 15.4 2.4

Metropolitan/suburban ................... 8,630 46.7 73.1 6.5 6.9 2.2

Nonmetropolitan ....................... 3,827 48.9 64.4 11.6 8.7 3.3

1The sum of the percents exceeds 100 because some women reported more than one source of payment for delivery.

2Includes births with missing data on source of payment.

3Limited to women 20–44 years of age at time of birth.

57
Table 29. Number of live birth deliveries in January 1984 or later to white women 15–44 years of age and percent of delivery costs paid

from specified sources, by selected characteristics of the mother: United States, 1988

Characteristic of the mother

Number of

births in

thousands

Source of payment for delivery

Self,

family, or

friends

Private

medical

insurance Medicaid

Other

government

All

other

Percent1

All live births2 ........................ 12,821 47.4 70.5 7.1 8.1 2.5

Education (at interview)3

Less than 12 years ..................... 1,877 47.1 33.2 15.5 21.8 *3.6

12 years ............................ 4,277 49.0 76.6 4.5 6.8 *2.7

13 years or more ...................... 5,523 47.2 85.2 *2.6 2.5 *2.0

Most recent occupation3

Professional or managerial ................ 2,629 45.1 90.9 *0.7 *1.5 *1.0

Technical, sales, or administrative ............ 4,845 52.0 80.1 *1.9 4.8 2.4

Service ............................ 2,010 46.6 63.3 8.8 10.5 *3.9

Farm, craft, or operative .................. 1,152 35.3 59.8 *13.3 15.4 *2.9

Never worked ........................ 1,040 51.7 36.5 *18.0 16.8 *3.9

Poverty level income (at interview)3

149 percent or less ..................... 2,649 44.3 33.1 17.3 22.9 5.7

150–299 percent ...................... 3,643 51.4 80.0 3.5 *3.2 *2.4

300 percent or more .................... 5,384 47.2 89.4 0.8 2.2 *1.1

Residence (at interview)

Metropolitan/central city .................. 2,244 38.9 55.9 13.0 15.3 *2.3

Metropolitan/suburban ................... 7,271 47.8 75.7 4.9 6.1 2.1

Nonmetropolitan ....................... 3,307 52.2 68.7 *7.8 7.5 3.4

1The sum of the percents exceeds 100 because some women reported more than one source of payment for delivery.

2Includes births with missing data on source of payment.

3Limited to women 20–44 years of age at time of birth.

58
Table 30. Number of live birth deliveries in January 1984 or later to black women 15–44 years of age and percent of delivery costs paid

from specified sources, by selected characteristics of the mother: United States, 1988

Characteristic of the mother

Number of

births in

thousands

Source of payment for delivery

Self,

family, or

friends

Private

medical

insurance Medicaid

Other

government

All

other

Percent1

All live births2 ........................ 2,374 26.6 40.1 32.8 15.6 *2.6

Education (at interview)3

Less than 12 years . . . . . . . . . . . . . . . . . . . . . 429 12.1 18.6 47.5 26.0 *2.7

12 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714 31.3 45.9 30.9 11.7 *1.6

13 years or more . . . . . . . . . . . . . . . . . . . . . . 655 32.8 67.7 15.9 8.0 *4.1

Most recent occupation3

Professional or managerial . . . . . . . . . . . . . . . . 182 29.0 84.5 *11.0 *0.5 *4.3

Technical, sales, or administrative . . . . . . . . . . . . 693 30.7 59.5 22.0 8.9 *1.5

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356 32.3 37.3 29.5 21.6 *1.0

Farm, craft, or operative . . . . . . . . . . . . . . . . . . 273 28.6 49.1 24.6 *14.1 *6.4

Never worked . . . . . . . . . . . . . . . . . . . . . . . . 294 *11.0 *7.1 62.0 23.5 *3.6

Poverty level income (at interview)3

149 percent or less ..................... 1,005 21.9 25.4 43.4 21.0 *2.4

150–299 percent . . . . . . . . . . . . . . . . . . . . . . 367 36.3 68.1 15.9 *6.2 2.1

300 percent or more . . . . . . . . . . . . . . . . . . . . 426 32.3 82.0 *7.7 *3.1 4.0

Residence (at interview)

Metropolitan/central city .................. 1,237 22.5 36.3 35.8 17.0 *1.8

Metropolitan/suburban . . . . . . . . . . . . . . . . . . . 742 31.2 49.9 25.1 13.7 *3.9

Nonmetropolitan . . . . . . . . . . . . . . . . . . . . . . . 395 30.7 33.3 37.8 *14.8 *2.4

1The sum of the percents exceeds 100 because some women reported more than one source of payment for delivery.

2Includes births with missing data on source of payment.

3Limited to women 20–44 years of age at time of birth.

59
Table 31. Number of women 15–44 years of age who had a live birth in January 1984 or later and percent distribution by source of

payment for most recent delivery, according to selected characteristics of the birth: United States, 1988

Characteristic of the birth

Number in

thousands Total

Own income

only

Insurance

only

Own income

and

insurance Medicaid

Other

government

All

other

Percent distribution

All women1 .......................... 12,340 100.0 11.4 36.9 31.1 8.7 7.4 4.6

Mother’s age at time of birth

Under 20 years ....................... 1,099 100.0 18.1 15.9 *16.9 27.9 18.6 *2.6

20–24 years ......................... 3,102 100.0 14.0 30.2 23.3 13.3 10.8 8.3

25–29 years ......................... 4,519 100.0 9.9 41.4 34.1 5.3 5.5 3.8

30–44 years ......................... 3,620 100.0 8.8 43.7 38.3 3.0 3.3 3.0

Mode of delivery

Cesarean section ...................... 2,943 100.0 7.4 36.8 38.5 7.5 6.0 3.7

Vaginal ............................ 9,349 100.0 12.6 36.9 28.8 9.0 7.8 4.9

Birthweight

Normal (2,500 grams or more) .............. 11,590 100.0 11.7 37.6 31.4 8.4 6.7 4.3

Low (less than 2,500 grams) . . . . . . . . . . . . . . . 750 100.0 *6.5 27.3 27.1 13.0 16.9 *9.2

Mother’s marital status at time of birth

Never married ........................ 1,898 100.0 11.0 17.0 7.5 34.0 23.3 7.2

Ever married ......................... 10,442 100.0 11.4 40.6 35.4 4.1 4.5 4.1

Wantedness status at conception

Intended ............................ 7,463 100.0 9.6 39.2 36.5 5.8 5.2 3.6

Mistimed ........................... 3,232 100.0 13.2 35.1 24.4 10.7 9.7 6.9

Unwanted ........................... 1,616 100.0 16.1 30.3 19.1 17.6 12.6 *4.4

1Includes births with missing data on payment for delivery, mode of delivery, or wantedness.

60
Table 32. Number of women 15–44 years of age who had a live birth in January 1984 or later and percent distribution by source of

payment for most recent delivery, according to selected characteristics of the mother: United States, 1988

Characteristic of the mother

Number in

thousands Total

Own income

only

Insurance

only

Own income

and

insurance Medicaid

Other

government

All

other

Percent distribution

All women1 .......................... 12,340 100.0 11.4 36.9 31.1 8.7 7.4 4.6

Race and ethnicity

Hispanic ............................ 1,539 100.0 24.5 23.6 21.1 16.2 11.5 *3.2

Non-Hispanic white ..................... 8,498 100.0 9.3 41.4 35.7 3.3 5.4 4.9

Non-Hispanic black ..................... 1,748 100.0 9.7 25.5 15.9 30.2 14.7 4.0

Non-Hispanic other . . . . . . . . . . . . . . . . . . . . . 554 100.0 *11.3 41.4 36.2 *2.3 *3.5 *5.4

Education (at interview)2

Less than 12 years ..................... 1,903 100.0 20.4 17.5 16.6 18.7 19.0 7.9

12 years ............................ 4,126 100.0 9.7 41.4 31.9 6.2 5.4 5.4

More than 12 years ..................... 5,079 100.0 7.9 45.2 38.9 2.8 2.2 3.1

Most recent occupation2

Professional or managerial ................ 2,333 100.0 5.3 50.4 40.5 1.0 0.5 2.3

Sales or clerical ....................... 4,615 100.0 9.9 42.9 36.1 3.3 3.6 4.2

Service ............................ 1,828 100.0 15.0 31.3 27.9 9.3 9.3 7.2

Farm, craft, or operative .................. 1,211 100.0 7.6 38.8 21.8 10.7 13.4 7.7

Never worked ........................ 1,121 100.0 21.4 12.2 19.9 24.7 16.5 5.4

Poverty level income (at interview)2

149 percent or less ..................... 2,902 100.0 18.8 16.3 14.9 21.0 18.9 10.2

150–299 percent ...................... 3,258 100.0 11.1 43.7 35.8 2.9 2.2 4.3

300 percent of higher .................... 4,948 100.0 5.7 49.3 40.6 1.0 1.5 2.0

Residence (at interview)

Metropolitan/central city .................. 2,779 100.0 10.9 32.9 20.0 17.7 14.8 3.7

Metropolitan/suburban ................... 6,671 100.0 10.7 41.2 34.4 4.9 4.5 4.3

Nonmetropolitan ....................... 2,890 100.0 13.3 30.9 34.2 8.6 7.0 6.0

1Includes births with missing data on payment for delivery.

2Limited to women 20–44 years of age at time of delivery.

61
Appendixes

Contents

I. Technical notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Background. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Statistical design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Measurement process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Data reduction and quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Reliability of estimates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Testing differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Nonsampling error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

II. Definitions of terms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Dependent variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Characteristics of pregnancies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Demographic terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

III. Items on the 1988 National Survey of Family Growth questionnaire related to health aspects of pregnancy and

childbirth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Appendix tables

I. Estimates of parameters A and B for relative standard error curves for the 1988 NSFG . . . . . . . . . . . . . . . . . . . . . . . . . 65

II. Approximate relative standard errors and standard errors for estimated number of total or other-than-black women:

1988 NSFG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

III. Approximate relative standard errors and standard errors for estimated number of black women: 1988 NSFG. . . . . . . 65

IV. Approximate standard errors for estimated percents expressed in percentage points for numbers of total or

other-than-black women: 1988 NSFG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

V. Approximate standard errors for estimated percents expressed in percentage points for pregnancies to all or

other-than-black women: 1988 NSFG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

VI. Approximate standard errors for estimated percents expressed in percentage points for pregnancies to black women:

1988 NSFG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

62
Appendix I

Technical notes

Background

This report is one of a series based on the National Survey

of Family Growth (NSFG), conducted by the National Center

for Health Statistics (NCHS). The NSFG was designed to

provide data on fertility, contraception, infertility, and other

aspects of maternal and infant health that are closely related to

childbearing.

The NSFG is a periodic survey based on personal interviews with a nationwide sample of women. The NSFG has

been conducted four times—in 1973, 1976, 1982, and 1988.

The present report is based primarily on the 1988 NSFG

(called Cycle IV), with some reference to trends since the

1982 survey (Cycle III). Interviewing for Cycles III and IV

was conducted under contract by Westat, Inc., in 1982 and

1988. A detailed description of the methods and procedures

used for Cycles III and IV are in two other publications

(31,105).

For Cycle IV, personal (face-to-face) interviews were

conducted between January and August, 1988, with a national

sample of 8,450 women who were 15–44 years of age as of

March 15, 1988, in the civilian, noninstitutionalized population of the United States. (In 1988, Alaska and Hawaii were

included in the sample for the first time.) In 1982, interviews

were conducted with 7,969 women 15–44 years of age from

the civilian noninstitutionalized population of the conterminous United States. In 1982, women were interviewed regardless of marital status for the first time.

In 1988 (Cycle IV), interviews were conducted with 8,450

women, including 2,771 black women, 5,354 white women,

and 325 women of other races. The interviews were conducted

by trained female interviewers in respondents’ homes and

lasted an average of 70 minutes. The interview focused on the

woman’s pregnancy history; her past and current use of

contraceptives; her physical ability to bear children (including

surgical sterilization and infertility); expectations for having

children in the future; use of medical services for birth control;

infertility; prenatal care; and a wide range of social, economic,

and demographic characteristics.

Statistical design

The NSFG is based on a multistage area probability

sample. Black households were sampled at higher rates than

other households so that reliable estimates of statistics could

be presented separately for black women. In addition, the

sample was designed to provide reliable estimates for each of

the four major geographic regions of the United States. The

sample was not large enough to produce estimates for individual states, counties, or other local areas.

The 8,450 women interviewed for the 1988 NSFG were

drawn from households in which someone had already been

interviewed for another NCHS survey, the National Health

Interview Survey (NHIS), between October 1985 and March

1987. The NHIS is a continuous survey of the civilian

noninstitutionalized population of the United States in which

data are collected for each household member on disabilities,

health conditions, doctor visits, hospitalizations, and other

health-related topics.

NCHS provided computer files of households that participated in the NHIS, along with information on addresses and

household composition. Households were included if a member had been interviewed between October of 1985 and March

of 1987, inclusively. The NSFG sample of households was

selected from 156 of the 198 primary sampling units (PSU’s)

in the NHIS design. (A PSU is a county or group of contiguous counties. The sampled PSU’s were located in nearly every

State and included all of the largest metropolitan areas in the

United States, as determined by the 1980 Census.) In comparison, Cycle III was confined to 79 PSU’s. The increased

dispersion of the sample resulted in smaller sampling errors in

1988 than in 1982.

The first step was to select households; the second was to

select women from those households. No more than one

woman was selected per household. Within each selected

household, all eligible women had an equal probability of

selection for the NSFG.

Interviewers were trained to trace the woman to her new

address if she had moved since her household’s participation

in the NHIS. After locating a sampled woman, the interviewer

conducted a brief ‘‘screener’’ interview to ascertain that she

was eligible for the NSFG.

The NSFG is designed to provide national estimates of

the number of women with particular characteristics—for

example, the number using oral contraceptives or the number

who are infertile. To make such estimates, each sample case

(woman) must be assigned a ‘‘sampling weight’’—a multiplier

that is the number of women in the population she represents.

In the 1988 NSFG, the final weights ranged from 197 to

54,997 and averaged about 6,852. They were derived by using

the following four basic steps:

63
+ Inflation by the reciprocal of the probability of selection—

The probability of selection is the product of the probabilities of selection of the PSU, segment, household, and

sample person within the household. This weight is called

the baseweight, or W0. For example, if the probability of

selection is 1 in 5,000, then W0 is 5,000.

+ Trimming—About 100 cases in the 1988 NSFG had

extremely large baseweights (largest W0 was greater than

50,000). In previous Cycles, these large weights were left

alone, but they could have large effects on estimates,

particularly among smaller categories of variables. To

reduce this problem, these large baseweights in Cycle IV

were trimmed to a maximum value of 8,000 for black

women (about 4 times the average W0 for black women)

and 19,000 for women who were not black (about 3 times

their average W0). The trimmed weight is called W1.

Trimming reduced the total weighted numbers to less than

the 57.9 million U.S. women who were known to be

15–44 years of age in 1988. These W1 weights underwent

up to two more iterations of trimming to yield the reduced,

trimmed weights (W3).

+ Nonresponse adjustment—For Cycle IV, 51 nonresponse

adjustment cells were identified, based on extensive analysis of response rates using variables available from the

NHIS (106). The trimmed weights were adjusted for

nonresponse using the cell-specific ratio of the weighted

sum of all cases to the weighted sum of all completed

cases (‘‘ratio-adjusted’’). For example, if the weight (W3)

for a particular case was 5,000, and that case is in a

nonresponse adjustment cell with a response rate of 80 percent, then the nonresponse adjusted weight for that case

would be 5,000/0.80, or 6,250. These new weights were

called ‘‘nonresponse adjusted weights’’ (W4).

+ Post-stratification by marital status, age, parity, and race—

The weights were then ratio-adjusted within each of a

72-cell matrix of categories of age (15–17, 17–19, 20–24,

25–29, 30–34, 35–39, and 40–44) by race (black versus

other-than-black), marital status (ever married versus never

married), or parity (0, 1, 2, 3, 4+). The control totals for

each of these 72 cells were obtained from the June 1988

Current Population Survey (CPS), conducted by the U.S.

Bureau of the Census.

The effect of this ratio adjustment process made the

sample more closely representative of the civilian noninstitutionalized population of women 15–44 years of age in the

United States. The final ‘‘post-stratification’’ yielded weights

(W5) that reduced the sample variances of the estimates for

most statistics.

Estimates of weighted numbers shown in the tables of this

report were rounded to the nearest thousand. Aggregate weights

and percents may not add to the total because of this rounding.

Measurement process

Field operations for Cycle IV were carried out by Westat,

Inc., under contract with NCHS. These operations included

interviewing several hundred women in a practice survey,

called a ‘‘pretest’’; selecting the sample; interviewing women

in the main survey; and performing specified quality control

checks on the completed questionnaires. Interviewers, all of

whom were female, were trained for one week before field

work. The first five interviews completed by each interviewer

were reviewed. After a high level of quality was achieved by

an interviewer, this review was reduced to a sample of

questionnaires, unless an unacceptable level of error was

found. A 10-percent sample of respondents was recontacted by

telephone to verify that the interview had taken place and that

certain key items had been accurately recorded.

A portion of the questionnaire used for this report is

reproduced in appendix III. Two forms of the questionnaire

were used, one for women 15–24 years of age and one for

women 25–44. The questionnaire for women 15–24 years old

included additional items that referred to early experiences

that women over 25 could not be expected to remember

accurately.

Data reduction and quality control

The responses of each woman to the interview questions

were coded into predetermined numerical codes and keyed

onto computer tapes. The first few questionnaires coded by

each coder were checked completely. After an acceptable level

of quality was reached, verification of coding was performed

on a systematic sample of each coder’s questionnaires. The

data were edited by computer to identify inconsistencies

between responses as well as code numbers not allowed in the

coding scheme. These errors were corrected.

Missing data on most of the variables used in this report

were imputed to provide consistent national estimates. (However, to speed release of the public use computer tape, not all

variables on the computer tape were imputed.)

Reliability of estimates

Because the statistics presented in this report are based on

a sample, they may differ somewhat from the figures that

would have been obtained if a complete census been taken

using the same questionnaires, instructions, interviewing personnel, and field procedures. This potential difference between

sample results and a complete count is referred to as a

sampling error.

Sampling error is measured by a statistic called the

standard error of estimate. The chances are about 68 in 100

that an estimate from the sample will differ from a complete

count by less than the standard error. The chances are about 95

in 100 that the difference between the sample estimate and a

complete count will be less than twice the standard error. The

relative standard error (RSE), or coefficient of variation, of an

estimate is obtained by dividing the standard error of the

estimate by the estimate itself and is expressed as a percent of

the estimate. Percents that have a relative standard error of

more than 30 percent are considered unreliable.

64
Estimation of standard errors

Because of the complex multistage design of the NSFG

sample, conventional formulas for calculating sampling errors

are inapplicable. Therefore, standard errors were estimated

empirically by using a technique known as balanced halfsample replication. This technique produces highly reliable,

unbiased estimates of sampling errors. Its application to the

NSFG has been described elsewhere (31).

Because it would be prohibitively expensive and cumbersome to estimate and publish a standard error for each percent

or other statistic by this technique, standard errors were

computed for selected statistics and population subgroups that

were chosen to represent a wide variety of demographic

characteristics and a wide variation in the size of the estimates

themselves. Curves were then fitted to the relative standard

error estimates (ratio of the standard error to the estimate

itself) for numbers of women according to the model

RSE (N ') = (A + B/N ')1⁄2

where N ' is the number of women and A and B are the

parameters whose estimates determine the shape of the curve.

Separate curves were fitted for women of all races combined,

for races other than black, and for black women, because a

different sampling rate was used for black women. Selected

estimates of A and B are shown in table I.

To calculate the estimated standard error or relative

standard error of an aggregate or percent, the appropriate

estimates of A and B are used in the equations:

RSEN' = (A + B/N')1⁄2

SEN' = (A + B/N')1⁄2 (N')

RSEP' = [[(B/P')(100 – P')]/X')]1⁄2

SEP' = ([(BP')(100 – P')]/X'))1⁄2

where

N' = number of pregnancies,

P' = percent,

X' = number of pregnancies in denominator of percent,

SE = standard error, and

RSE = relative standard error.

Tables II, III, IV, V, and VI show some illustrative

standard errors of aggregates and percents for women from

Cycle IV of the NSFG. Similar figures for Cycle III are found

in the earlier report (22).

Testing differences

The standard error of a difference between two comparative statistics, such as the proportion of white women using the

pill compared with the proportion of black women using the

pill, is approximately the square root of the sum of the squares

of the standard errors of the statistics considered separately, or

calculated by this formula: If

d = P'

1 – P'2

then

Sd = ' [(P'

1)

2

(RSEp'1)

2 + (P'

2)

2

(RSEp'2)

2

]

where P'

1 is the estimated percent for one group and P'2 is the

estimated percent for the other group, and RSEp'1 and RSEp'2

Table I. Estimates of parameters A and B for relative standard

error curves for the 1988 NSFG

Parameter

set Characteristic

Estimated parameters

A B

I Number of pregnancies for total of

other-than-black women –0.000047 13,216

II Number of pregnancies for black

women 0.000961 3,307

III Number of total of

other-than-black women –0.00018 10,738

IV Number of black women –0.000626 5,181

Table II. Approximate relative standard errors and standard

errors for estimated number of total or other-than-black women:

1988 NSFG

Size of estimate

Relative standard

error (in percent)

Standard

error

100,000 ............. 32.0 32,000

250,000 ............. 20.4 51,000

500,000 ............. 14.4 72,000

1,000,000 ............ 10.2 102,000

5,000,000 . . . . . . . . . . . . 4.4 221,000

10,000,000 . . . . . . . . . . . 3.0 298,000

20,000,000 . . . . . . . . . . . 1.9 377,000

30,000,000 . . . . . . . . . . . 1.3 400,000

50,000,000 . . . . . . . . . . . 0.6 294,000

58,000,000 . . . . . . . . . . . 0.2 131,000

Table III. Approximate relative standard errors and standard

errors for estimated number of black women: 1988 NSFG

Size of estimate

Relative standard

error (in percent)

Standard

error

100,000 ............. 22.0 22,000

250,000 ............. 14.0 35,000

500,000 . . . . . . . . . . . . . 9.8 49,000

1,000,000 . . . . . . . . . . . . 6.7 67,000

5,000,000 . . . . . . . . . . . . 2.0 101,000

7,500,000 . . . . . . . . . . . . 0.8 60,000

Table IV. Approximate standard errors for estimated percents

expressed in percentage points for numbers of total or

other-than-black women: 1988 NSFG

Base of percent

Estimated percent

2 or

98

5 or

95

10 or

90

20 or

80

30 or

70

40 or

60 50

Standard error in percentage points

100,000 . . . . . . . . . . . . . 4.6 7.1 9.8 13.1 15.0 16.1 16.4

500,000 . . . . . . . . . . . . . 2.1 3.2 4.4 5.9 6.7 7.2 7.3

1,000,000 . . . . . . . . . . . . 1.5 2.3 3.1 4.1 4.7 5.1 5.2

5,000,000 . . . . . . . . . . . . 0.6 1.0 1.4 1.9 2.1 2.3 2.3

10,000,000 . . . . . . . . . . . 0.5 0.7 1.0 1.3 1.5 1.6 1.6

30,000,000 . . . . . . . . . . . 0.3 0.4 0.6 0.8 0.9 0.9 0.9

50,000,000 . . . . . . . . . . . 0.2 0.3 0.4 0.6 0.7 0.7 0.7

58,000,000 . . . . . . . . . . . 0.2 0.3 0.4 0.5 0.6 0.7 0.7

65
are the relative standard errors of P'

1 and P'2. This formula

represents the actual standard error accurately for the difference between separate and uncorrelated characteristics, although

it is only an approximation in most other cases.

A difference among comparable proportions or other

statistics from two or more subgroups is considered statistically significant when a difference of that size or larger would

be expected by chance in fewer than 5 percent of repeated

samples of the same size and type, if no true difference existed

in the populations sampled (also known as Type I error or

alpha level). Such a difference would be statistically significant at the 0.05 level. By this criterion, if the observed

difference or a larger one could be expected by chance in more

than 5 percent of repeated samples, then one cannot be

sufficiently confident to conclude that a real difference exists

between the populations. When an observed difference is large

enough to be statistically significant, the true difference in the

population is estimated to lie between the observed difference

plus or minus two standard errors of that difference in 95 of

100 samples.

Although the 5-percent criterion is conventionally applied,

it is arbitrary. Depending on the purpose of the particular

comparison, a different level of significance may be more

useful. For greater confidence, one would test for significance

at the 0.01 (1-percent) level. However, if one can accept a

10-percent chance of concluding that a difference exists when

there actually is none in the population, a test of significance

at the 10-percent level would be appropriate.

In this report, terms such as ‘‘similar’’ and ‘‘no difference’’ mean that any observed difference between two estimates being compared is not statistically significant. Terms

relating to difference (for example, ‘‘greater,’’ ‘‘less,’’ ‘‘larger,’’

and ‘‘smaller’’) indicate that the observed differences are

statistically significant at the 5-percent alpha level. Statements

about differences that are qualified (by phrases such as ‘‘the

data suggest’’ and ‘‘some evidence’’) indicate that the difference is significant at the 10-percent alpha level but not at the

5-percent level. Individual t-tests, with a critical value of 1.96

(0.05 alpha level), were used to test all comparisons. This

strategy, although it highlights major findings, does not take

into account hypothesis testing issues associated with multiple

comparisons, where a statistic is potentially compared for

more than two domains. Lack of comment regarding the

difference between any two statistics does not mean the

difference was tested and found to be not significant.

When a substantial observed difference is found not to be

statistically significant, one should not conclude that no difference exists. It means that such a difference cannot be established with 95-percent confidence from this sample. This is

especially important for estimates based on smaller subgroups

of women, such as Hispanic women or teenagers. Furthermore, lack of comment about any two statistics does not mean

that the difference was tested and found not to be significant.

The number of replicates in the balanced half-sample

replication design minus one (99 in Cycle IV) can reasonably

be used as an estimate of the number of degrees of freedom. A

two-tailed t-test with 99 degrees of freedom is equivalent to a

two-tailed normal deviate z-test. For example, in the years up

to and including 1988, 14.2 percent of the 10,670,000 births to

black women and 6.1 percent of the 55,437,000 births to white

women were low birthweight. To test this racial difference at

the 0.05 level of significance, compute

z = 14.2 – 6.1

' [(14.2)2 RSE 2

(14.2) + (6.1)2 RSE2(6.1)]

Relative standard errors are computed using the appropriate

values for B from table I:

RSE14.2 = [([3,307/(14.2)][100–14.2])/10,670,000]1/2

= 0.043

RSE6.1 = [([13,216/(6.1)][100–6.1])/55,437,000]1/2

= 0.061

thus

z = 11.34

The two-tailed 0.95 critical value (1–α) for a z statistic is 1.96.

Therefore, the difference is significant at the 5-percent level.

Nonsampling error

Although sampling errors affect the reliability (that is,

precision, repeatability) of survey estimates, nonsampling

Table V. Approximate standard errors for estimated percents

expressed in percentage points for pregnancies to all or

other-than-black women: 1988 NSFG

Base of percent

Estimated percent

2 or

98

5 or

95

10 or

90

20 or

80

30 or

70

40 or

60 50

Standard error in percentage points

100,000 . . . . . . . . . . . . . 5.1 7.9 10.9 14.5 16.7 17.8 18.2

250,000 . . . . . . . . . . . . . 3.2 5.0 6.9 9.2 10.5 11.3 11.5

500,000 . . . . . . . . . . . . . 2.3 3.5 4.9 6.5 7.5 8.0 8.1

1,000,000 . . . . . . . . . . . . 1.6 2.5 3.4 4.6 5.3 5.6 5.7

5,000,000 . . . . . . . . . . . . 0.7 1.1 1.5 2.1 2.4 2.5 2.6

10,000,000 . . . . . . . . . . . 0.5 0.8 1.1 1.5 1.7 1.8 1.8

20,000,000 . . . . . . . . . . . 0.4 0.6 0.8 1.0 1.2 1.3 1.3

30,000,000 . . . . . . . . . . . 0.3 0.5 0.6 0.8 1.0 1.0 1.0

50,000,000 . . . . . . . . . . . 0.2 0.4 0.5 0.7 0.7 0.8 0.8

75,000,000 . . . . . . . . . . . 0.2 0.3 0.4 0.5 0.6 0.7 0.7

100,000,000 . . . . . . . . . . 0.2 0.3 0.3 0.5 0.5 0.6 0.6

Table VI. Approximate standard errors for estimated percents

expressed in percentage points for pregnancies to black women:

1988 NSFG

Base of percent

Estimated percent

2 or

98

5 or

95

10 or

90

20 or

80

30 or

70

40 or

60 50

Standard error in percentage points

100,000 . . . . . . . . . . . . . 2.9 4.6 6.3 8.4 9.6 10.3 10.5

250,000 . . . . . . . . . . . . . 1.9 2.9 4.0 5.3 6.1 6.5 6.6

500,000 . . . . . . . . . . . . . 1.3 2.0 2.8 3.8 4.3 4.6 4.7

1,000,000 . . . . . . . . . . . . 0.9 1.4 2.0 2.7 3.0 3.3 3.3

5,000,000 . . . . . . . . . . . . 0.4 0.6 0.9 1.2 1.4 1.5 1.5

10,000,000 . . . . . . . . . . . 0.3 0.5 0.6 0.8 1.0 1.0 1.0

25,000,000 . . . . . . . . . . . 0.2 0.4 0.5 0.7 0.8 0.8 0.9

66
error may introduce bias (that is, inaccuracy). The results of

any survey are subject to at least four types of nonsampling

error: interview nonresponse; nonresponse to individual questions or items within the interview; inconsistency of responses

to questions; and error of recording, coding, and keying by

survey personnel.

To minimize nonsampling error, stringent quality control

procedures were introduced at every stage of the survey. This

includes a check on completeness of the household listing;

extensive training and practice of interviewers; editing of

questionnaires by the interviewers’ supervisors; short verification interviews with a subsample of respondents; verification

of coding and editing; independent coding of a sample of

questionnaires by NCHS; keypunch verification; and an extensive computer ‘‘cleaning’’ to check for inconsistent responses,

missing data, and invalid codes. A detailed description of some

of these procedures follows; others were discussed above.

Interview nonresponse

Interview nonresponse means that no part of an interview

was obtained. This is conventionally measured by response

rates. Nonresponse to the NHIS was 4 percent, for a response

rate of 96 percent. Among this 96 percent, 82.5 percent of

eligible women responded to the NSFG, for a compound

response rate of 79 percent. Nonresponse varied by certain

characteristics of the woman, but the wealth of information in

the NHIS allowed adjustments to be made for nonresponse.

This nonresponse, and the procedures used to adjust for it, are

described elsewhere (28,105,106).

Item nonresponse

Item nonresponse may have occurred when a respondent

refused to answer a question, when she did not know the

answer to a question, when the question was erroneously

skipped or the answer was not recorded by the interviewer, or

when the answer could not be coded. The rate of nonresponse

to individual questions was very low in Cycle IV, as it was in

Cycle III. Some examples of item nonresponse from among a

total of 8,450 respondents are as follows: religion, 25 cases;

occupation, 17 cases. The items with the most nonresponse

were family income (from which poverty-level income was

derived), with 893 cases, and age (date) of first intercourse,

with 458 missing cases. In the 1988 NSFG, 201 items were

forced to be complete; missing data for these variables were

imputed. Of these 201 items, 173 imputed items with imputation flags exist on the public-use tape. For 116 of these 173

items, less than 1 percent of the cases required imputation; for

39, 1–5 percent; for 13, 5–10 percent; and for only 5,

10–11 percent. For those few items for which the proportion

of cases imputed was high, this fact is noted in the appropriate

section of the definitions. This report only used NSFG variables with imputed missing data.

As with all survey data, responses to the NSFG were

subject to deliberate misreporting by the respondent. Such

misreporting cannot be detected directly, but it can be detected

indirectly by the extensive computer ‘‘cleaning’’ and editing

procedures used in the NSFG.

67
Appendix II

Definitions of terms

Dependent variables

Timing of first prenatal visit—For pregnancies ending in a

live birth in 1984–88, women in the 1988 NSFG were asked:

‘‘During this pregnancy, did you ever visit a doctor or clinic

for prenatal care?’’ Women were instructed not to include

visits consisting only of a pregnancy test. Women who answered

‘‘yes’’ were then asked: ‘‘How many weeks or months had you

been pregnant when you first visited a doctor, midwife, or

clinic for prenatal care?’’ Women who answered that they

were less than a month, 1 month, or 2 months pregnant are

classified as beginning prenatal care in the first trimester, or at

‘‘less than 3 months.’’ The other categories are ‘‘3 or 4 months

pregnant’’ and ‘‘5 months (pregnant) or more or no care.’’

Several reports have examined the proportion of births

receiving first trimester prenatal care across different data

sources. The three national data sources commonly compared

are: birth certificates (42,45,107), the 1980 National Natality

Survey (NNS) (108), and the National Survey of Family

Growth (NSFG) (45). Because the questions are worded and

administered differently in these three sources, the proportions

reporting first-trimester care differ (45). However, in one

recent study the largest differences are seen in the first 1 or 2

months of pregnancy, which suggests that (a) the stage at

which pregnancies are recognized varies among sources of

data; (b) data sources other than the NSFG may be counting

pregnancy tests as first prenatal visits; and (c) mothers report,

but physicians may sometimes be unaware of, early visits to

other providers of prenatal care (45).

Source of most prenatal care—Women who reported that

they visited a doctor, midwife, or clinic for prenatal care (for

pregnancies ending in 1984–88) were asked: ‘‘To which of the

places on the card did you go for most of your prenatal care

visits?’’ Women were then shown a card listing the following

types of medical facilities and asked to choose one category

that best described the place.

A. Community health center clinic . . . . . . . . . . . . . . . . 01

B. Public health department clinic . . . . . . . . . . . . . . . . 02

C. Family planning clinic . . . . . . . . . . . . . . . . . . . . . . . 03

D. Hospital clinic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 04

E. Private doctor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 05

F. Private group practice, co-op, or private clinic . . . . 06

G. HMO or other prepaid group practice . . . . . . . . . . . 07

H. Other (specify) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 08

In this report, women who answered E, F, or G were

classified as receiving care from a ‘‘private doctor;’’ women

who answered D, as using a ‘‘hospital clinic;’’ and those who

answered A, B, C, or H, as using ‘‘other clinic.’’ Sample sizes

are not large enough to allow separate analyses of use of the

different types of clinics.

Cigarette smoking during pregnancy—Women in the NSFG

who had ever been pregnant and who reported smoking at all

during the 12 months before their most recent pregnancy

ended were asked: ‘‘On the average, how many cigarettes did

you smoke per day after you found out that you were

pregnant?’’ The responses were coded in the following

categories:

About one a day or less ........................ 1

Just a few (2–4) .............................. 2

About half a pack (5–14) ....................... 3

About a pack (15–24).......................... 4

About 11⁄2 packs (25–34) ....................... 5

About 2 packs (35–44) ......................... 6

More than 2 packs (45 or more) ................. 7

Didn’t smoke during (last) pregnancy . . . . . . . . . . . . 96

In this report, women in categories 1, 2, and 3 were

classified as having smoked fewer than 15 cigarettes per day.

Those in categories 4, 5, 6, and 7 were classified as having

smoked 15 or more per day. Women in category 96, as well as

women who reported no smoking in the 12 months before the

pregnancy ended, were labeled as ‘‘did not smoke at all.’’

Women who were currently pregnant were excluded from

the statistics on smoking and drinking during the most recent

pregnancy, as were women whose most recent pregnancies

ended in induced abortion. In contrast, in a previous report

(109), currently pregnant women were included in the tables

showing smoking and drinking during pregnancy, but excluded

from the statistics by age at pregnancy outcome. In this report,

they were excluded entirely so the totals would be more

consistent throughout the tables and so that the data would

refer only to completed pregnancies. Induced abortions were

excluded in order to permit meaningful analysis of factors

such as wantedness and timing of prenatal care, which would

be particularly sensitive for women who terminated their

pregnancies. Furthermore, because of this sensitivity, these

questions were not asked for pregnancies ending in induced

abortion.

Alcohol consumption during pregnancy—Women in the

NSFG who had ever been pregnant were also asked: ‘‘During

68
your (last) pregnancy, how often did you usually drink alcoholic beverages, that is, beer, wine, or liquor?’’ The response

categories were:

Every day ................................... 1

Nearly every day.............................. 2

3 or 4 days a week ............................ 3

1 or 2 days a week ............................ 4

3 or 4 days a month ........................... 5

About once a month ........................... 6

Less than once a month ........................ 7

Not at all . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

In this report, women in category 96 were classified as

‘‘did not drink at all,’’ women in category 7 were classifed as

drinking ‘‘less than once a month,’’ women in category 6 as

drinking ‘‘once a month,’’ and those in categories 1–5 as

drinking ‘‘more than once a month.’’

Low birthweight—A ‘‘low birthweight’’ baby is one who

weighs 2,500 grams (5 pounds 8 ounces) or less at birth.

Statistics on birthweight in this report are shown only for

single live births because multiple births often have lower

birthweights. For all births in the NSFG, women were asked:

‘‘How much did [child’s name] weigh at birth?’’

Women who could not remember were then asked: ‘‘Did

[child’s name] weigh more than 5 pounds, 9 ounces or less?’’

As noted in the text, births in this report occurred during

a period of several years up to and including 1988 and are

based on a sample. However, births in the vital statistics

system occurred during a specified calendar year and are based

on birth certificates. (In most states, statistics on birthweight

were based on all birth certificates. In selected states, data on

birthweight were based on a 50-percent sample of birth

certificates.)

Source of payment for delivery—Women who had had

one or more live births were asked the following question for

each live birth in 1984–88: ‘‘This card lists some of the ways

in which medical bills can be paid. When [child’s name] was

born, in which of these ways was the bill paid?’’ The woman

was then handed a card containing the following categories:

Your (or your husband’s/partner’s) own income ..... 1

Parents, other relatives, boyfriend or his family ..... 2

Insurance (which you carry or is carried for you) . . . 3

No charge—paid by Medicaid ................... 4

Government assistance other than Medicaid (State or

local) ...................................... 5

Some other way (specify)....................... 6

Women could choose as many responses as applied.

Therefore the percents given in tables 27–32 add up to more

than 100 percent. Responses to categories 1 and 2 were

combined to form the category ‘‘self, family, or friends;’’

category 3 is labeled ‘‘private medical insurance’’ in tables

27–32; category 4, ‘‘Medicaid;’’ category 5, ‘‘other government;’’ and category 6, ‘‘all other.’’

For tables 31–32, a source of payment variable was

created with mutually exclusive categories that add up to

100 percent. The categories are ‘‘self, family, or friends only,’’

‘‘private insurance only,’’ ‘‘self, family, friends, and insurance

only,’’ ‘‘Medicaid only,’’ ‘‘other government only,’’ and ‘‘all

other combinations of payment.’’

Characteristics of pregnancies

Age at birth or pregnancy outcome—Each woman was

asked the month, day, and year each pregnancy ended. Her

date of birth was subtracted from the date of the pregnancy

outcome to compute her age in completed years when the

child was born or the pregnancy otherwise ended.

Birth order or pregnancy order—Births are classified by

birth order. Where the birth order is ‘‘first,’’ the birth was the

woman’s first birth; where it is ‘‘second,’’ the birth was the

woman’s second birth. Similarly, where the pregnancy order is

‘‘first,’’ it was the woman’s first pregnancy; where it is

‘‘second,’’ it was the woman’s second pregnancy.

Mode of delivery—For each pregnancy, women were

asked to identify the way or ways in which the pregnancy

ended, using the following categories:

Miscarriage .................................. 1

Stillbirth..................................... 2

Abortion..................................... 3

Birth by cesarian section ....................... 4

Birth by vaginal delivery ....................... 5

Mode of delivery was classified as ‘‘cesarian section’’ if the

woman responded with 4 and as ‘‘vaginal delivery’’ if she

answered with 5.

Marital status at birth or pregnancy outcome—If the date

of the baby’s birth was before the date of the woman’s first

legal marriage, the woman was classified as ‘‘never married at

birth;’’ if the date of the baby’s birth was after the date of her

first legal marriage, she was classified as ‘‘ever married at

birth.’’ The same procedure was used for other pregnancy

outcomes.

Wantedness status at conception—The specific terms

‘‘intended,’’ ‘‘mistimed,’’ and ‘‘unwanted’’ used in this report

refer to the woman’s attitude toward her pregnancy at the time

she became pregnant.

The series of questions from which the variables were

derived to classify pregnancies as intended, mistimed, or

unwanted at conception in the 1988 NSFG were:

+ ‘‘At the time you became pregnant with [baby’s name],

did you yourself, actually want to have a(nother) baby at

some time?’’

+ ‘‘It is sometimes difficult to recall these things but, just

before that pregnancy began, would you say that you

probably wanted a(nother) baby at some time?’’

+ ‘‘Did you become pregnant sooner than you wanted, later

than you wanted, or at about the right time?’’

Pregnancies were classified as:

+ Intended if the woman reported becoming pregnant at

about the right time or later than she wanted, or if she did

not care when she became pregnant;

+ Mistimed if she wanted a baby eventually, but not as soon

as the pregnancy occurred (for example, if she became

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pregnant at age 19 but had wanted to wait until she was

22); and

+ Unwanted if she never wanted that pregnancy (for example,

if she wanted only one child, already had one, and became

pregnant again).

It is important to emphasize that an ‘‘unwanted pregnancy’’ does

not necessarily mean an ‘‘unwanted child.’’ Many children who

were not wanted at conception become cherished members of

their families.

Demographic characteristics of women

Race—Women were asked to identify which of the following groups best described their racial background:

+ Alaskan native or American Indian

+ Asian or Pacific Islander

+ Black

+ White

Race was also recorded based on interviewer observation, but

for this report, race was based on respondent’s self-report and

classified as black, white, or other.

Hispanic origin—A respondent was classified as being of

Hispanic origin if she reported that her only or principal

national origin was Puerto Rican, Cuban, Mexican American,

Central or South American, or other Spanish. In selected tables

presenting maternal characteristics, race and Hispanic origin

were used to classify women as Hispanic, non-Hispanic white,

non-Hispanic black, or non-Hispanic other. The numbers of

Hispanic women in the survey were too small to be subdivided

by other characteristics and yield reliable national estimates.

Education—Education was classified according to the highest grade or year of regular school or college completed. Tables in

this report present each woman’s educational level at the time of

interview, which may not be the same as at the time of her

pregnancies. The categories used are ‘‘less than 12 years,’’ ‘‘12

years’’ (high school), and ‘‘13 years or more.’’ Because teenage

women are likely to fall into the first category due solely to their

age, many tables in this report show education level only for

women aged 20–44 years at pregnancy outcome.

Most recent occupation—Women who were working at

the date of interview were asked: ‘‘What is your occupation?

That is, what is your job called?’’ ‘‘What are your most

important activities or duties?’’ ‘‘What kind of business or

industry do you work for? That is, what do they make or do?’’

Women who had worked in the past but were not currently working were asked: ‘‘What was your last occupation?

That is, what was your job called?’’ ‘‘What were your most

recent activities or duties?’’ ‘‘What kind of business or industry did you work for? That is, what did they make or do?’’

The answers to these questions were recorded verbatim and

used by specially trained occupation coders to find the most

appropriate standard job title in the 1980 U.S. Census classification. Where more than one occupation was given, the primary or

first-mentioned occupation was coded. Occupations were coded

using the 3-digit codes used by the U.S. Bureau of the Census.

However, for this report they have been grouped into the following major categories:

+ Professional or managerial occupation

+ Technical, sales, or clerical occupation

+ Service occupation

+ Farmwork, craft, or operative occupation

+ Never worked

As with the education variable, many tables in this report

show job status only for women aged 20–44 years at pregnancy outcome because teenage women may still be in school,

thus more likely to be classified as ‘‘never worked.’’

Poverty level income—The poverty index ratio was calculated by dividing the total family income by the weighted

average threshold income of families whose head of household was under 65 years of age, based on the 1987 poverty

levels defined by the U.S. Census Bureau and shown in

Current Population Reports (110). This definition of poverty

status takes into account the sex of the family head and the

number of persons in the family. Total family income includes

income from all sources for all members of the respondent’s

family. For example, for a family of four in 1987, the poverty

level was $11,611. So, if a family of four had an income of

$30,000, their poverty level income would be 30,000/11,611,

or 258 percent. This respondent would be classified in the

second of three categories used for this report: ‘‘149 percent or

less,’’ ‘‘150–299 percent,’’ or ‘‘300 percent or more.’’

As with education level and job status variables, many

tables in this report show poverty level income only for

women aged 20–44 years at pregnancy outcome. Teenage

women living on their own are more likely to be poor. If they

are living with parents, they are more likely to respond with

‘‘don’t know’’ to the total family income question.

For a substantial number of respondents (893 or 11 percent), total family income was not ascertained. These missing

values were imputed using a known value of another similar,

randomly selected respondent. Because of this high level of

missing data, small differences by poverty level income should

be interpreted with caution.

Medicaid status—In Cycle III, NSFG respondents were

asked, ‘‘Are you yourself now covered by Medicaid [State name

for Medicaid], or do you have a card that looks like this?’’ The

respondent was then shown a Medicaid card for her State. Cycle

IV of the NSFG did not include this direct question. For this

report, women who received Medicaid payments for prenatal care

or for delivery costs were classified as ‘‘Medicaid recipients.’’

There is potential for misclassification with this approach, but the

comparability of NSFG data on Medicaid coverage with other

national data sources strengthens its plausibility.

Place of residence—The U.S. Office of Management and

Budget defines metropolitan statistical areas (MSA’s). Places of

residence in the 1988 NSFG were classified into three categories,

based on 1980 Census population counts: central cities of metropolitan areas, suburban parts of metropolitan areas, and nonmetropolitan areas. Women in the first two categories are often

referred to in this report as ‘‘metropolitan’’ residents, while those

in the last category are referred to as ‘‘nonmetropolitan area’’

residents. Nonmetropolitan areas may include both rural and

urban places of residence.

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Appendix III

Items on the 1988 National

Survey of Family Growth

questionnaire related to

health aspects of pregnancy

and childbirth

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DHHS Publication No. (PHS) 95-1994, Series 23, No. 18

5-1274 (8/95)

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