Data from the

NATIONAL VITAL STATISTICS SYSTEM

Characteristics of Births

United States, 1973-1975

A presentation of characteristics of live births, including educational attainment of parents, birth weight, period of gestation, prenatal care, sex ratio, month of birth, attendant at birth and place of

delivery, plurality, illegitimacy, and interval since last live birth and

last pregnancy, and outcome of last pregnancy. Emphasis is on

births occurring in 1973; however, data for 1974 and 1975 are included in the summary and in the discussion of trends.

DHEW Publication No. (PHS) 78-1908

Series 21

Number 30

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE

Public Health Service

National Center for Health Statistics

‘ Hyattsville, Md. September 1978
Library of Congrass Cataloging in Publication Data

Querec, LindaJ.

Characteristics of births.

(Vital and health statistics: Series 21, Data from the National Vital Statistics System;

no. 30) (DHEW publication no. (PHS) 78-1908)

Bibliography: p. 27

1. Childbirth–United States–Statistics. 2. Prenatal care–United States–Statistics.

I. Spratley, EmelI, joint author. II. Title. 111. Series: United States. National Center for

Health Statistics. Vital and health statistics: Series 21, Data from the National Vital Statistics system, Data on natalit y, marriage, and divorce; no. 30. IV. Series: United States. Dept.

of Health, Education, and Welfare. DHEW publication no. (PHS) 78-1908. [DNLM: 1. Vital

statistics–United States. W2 A N148vu no. 30]

HA211.A3 no. 30 [HB915] 312’.1’73s [312’.1’73]

ISBN 0-8406 -0135-2 78-15448

—

For sale by the Superintendent of Documents, U.S. Government Printing Offke

Washington, D. C. 20402

Stock No. 017-022A2C64C-5
NATIONAL CENTER FOR HEALTH STATISTICS

DOROTHY P. RICE, Director

ROBERT A. ISRAEL, Deputy Director

JACOB J. FELDMAN, Ph.D., Associate Director for AYzalysis

GAIL F. FISHER, Ph. D., Associate Director for the Cooperative Health Statistics System

ELIJAH L. WHITE, Associate Director for Data Systems

JAMES T. BAIRD, JR,, Ph.D., Assockzte Director for International Statistics

ROBERT C. HUBER, Associate Director for Management

MONROE G. SIRKEN, Ph. D., Associate Director for Mathematical Statistics

PETER L. HURLEY, Associate Director for Operations

JAMES M. ROBEY, Ph. D., Associate Director for Program Development

PAUL E. LEAVERTON, Ph. D., Associate Director for Research

.4LICE HAYWOOD, Information Officer

DIVISION OF VITAL STATISTICS

JOHN E. PATTERSON, Director

ALICE M. HETZEL, Deputy Director

ROBERT L. HEUSER, M. A., Chiej Natality Statistics Branch

RITA U. HOFFMAN, Chiej Programming Branch

MABEL G. SMITH, Acting Chiej Statistical Resources Branch

Vital and Health Statistics-Series 21-No. 30

DHEW Publication No. (PHS) 78-1908

Library of Congress Catalog Card Number 78-15448
CONTENTS

Introduction ...........................................................................................................................................

Summary of PrincipaI Findkgs .............................................................................................................

Education ..............................................................................................................................................

Education of Mother ........................................................................................................................

Education of Father .........................................................................................................................

Birth Weight ..........................................................................................................................................

Education of Mother ........................................................................................................................

Period of Gestation ...............................................................................................................................

Education of Mother ........................................................................................................................

Month of Pregnancy Prenatal Care Began ..............................................................................................

Percent Low Birth Weight ................................................................................................................

Education of Mother ........................................................................................................................

Number of Prenatal Vkits .....................................................................................................................

Percent Low Birth Weight ................................................................................................................

Education of Mother ........................................................................................................................

Sex Ratio of Births ................................................................................................................................

Month of Birth ......................................................................................................................................

Attendant at Birth and Place of Delivery ...............................................................................................

Multiple Births ......................................................................................................................................

Interval Since Last Live Birth ................................................................................................................

Education of Mother ........................................................................................................................

Interval Since Termination of Last Pregnancy and Outcome of Last Pregnancy ....................................

Percent Low Birth Weight ................................................................................................................

Illegitimacy ...........................................................................................................................................

Education of Mother ........................................................................................................................

Percent Low Birth Weight ................................................................................................................

Prenatal Care ....................................................................................................................................

References .............................................................................................................................................

List of Detailed Tables ..........................................................................................................................

Appendix: Techticd Notes ...................................................................................................................

LIST OF FIGURES

1. Percent of Eve births prematwe, byageof motiermd mce:totd of40repotiing States mdtie

District of Columbi~ 1973 ..........................................................................................................

2. Median birth weight bypenod ofgestation adrace: totdof40 repofiing States mdtie District

of Cohunbia, 1973 .......................................................................................................................

1

1

2

2

3

3

5

5

7

7

8

9

10

10

11

11

13

14

16

17

19

19

20

20

24

24

25

27

28

46

6

7

...

Ill
3. Percent of births tomothers beginning prenat.al care during the first Zmonths ofpregnancy, by

ageofmotherand race and Iive-birth order and race: total of 42 reporting States and the Di<trict

of Columbia, 1973 .......................................................................................................................

4. Sexratio bymonth of birth andrace: United States, 4-year average, l97O-73 ...............................

5. Monthly indexes oflivebirths, byrace: United States andeachre@on, l973 ................................

6. Percent of Iivebirths occuming inhospitds, bycolor: United States, 1960-75 ...............................

7. Mean interval since last live birth, by age of mother and live-birth order: total of 40 reporting

States andthe District of Columbia, 1973 ...................................................................................

8. Estimated ille@timacy rates, bya~ofmother andcoIor: United States, l94O-75 .........................

LIST OF TEXT TABLES

A. Perceot of live births of 2,500 grams or less by age of mother and live-birth orde~ United States,

1973 ............................................................................................................................................

B. Percent distribution of live births by period of gestation and race: total of 40 reporting States

and the District of Columbia, 1973 .............................................................................................

C. Percent of live births premature by race and educational attainment of mother: total of 37 reporting States and the District of Columbia, 1973 .......................................................................

D. Percent of live births of 2,500 grams or less for each month of pregnancy prenatal care began,

by race: total of 42 reporting States and the District of Columbia, 1973 ....................................

E. Median number of prenatal visits by month of pregnancy prenatal care began and race: total of

37 reporting States and the District of Cohsmbia, 1973 ...............................................................

F. Percent of live births of 2,500 grams or less by number of prenataf visits and race: total of 38

reporting States and the District of Columbia, 1973 ....................................................................

G. Median number of prenataI visits by educational attainment of mother and race: totaf of 37 reporting States and the District of Columbia .................................................................................

H. Sex ratio by race: United States, 4-year average, 1970-73 ..............................................................

J. Sex ratio at birth by race and plurality: United States, 1971-75 ....................................................

K. Sex ratio at birth by live-birth order and age of mother: United States, 1973 ................................

L. Monthly indexes of live births and standard deviations: United States, 1960, 1970, 1973, and

1975 ............................................................................................................................................

M. Ratio of plural live births to total live births by age of mother and race: United States, 1973 .......

N. Median birth weight and percent of live births of 2,500 grams or less, by plurality and race:

United States, 1973 .....................................................................................................................

O. Mean interval since last live birth by live-birth order, age of mother, and race: totaf of 40 reporting States and the District of Cohrmbia, 1973 .......................................................................

P. Mean interval since termination of last pregnancy by outcome of last pregnancy, live-birth

order, and age of mother: total of 39 reporting States and the Dktrict of Columbia, 1973 .........

Q. Estimated illegitimacy rates by age of mother and race: United States, 1970-75 ............................

R. Estimated illegitimacy ratios by age of mother and race: United States, 1973 ...............................

S. Percent of live births illegitimate by educational attainment of mother and race: totrd of 33

reporting States and the District of Columbia, 1973 ....................................................................

8

13

14

15

18

22

4

6

7

9

10

11

11

12

12

13

16

16

17

20

23

24

24

iv
T. Percent of live births of 2,500 grams or less by legitimacy status, age of mother, and race: totrd

of 38 reporting States and the District of Columbia, 1973 .......................................................... 25

U. Percent of live bkths of 2,500 grams or less by educational attainment of mother, legitimacy

status, and race: total of 33 reporting States and the District of Columbia, 1973 ........................ 25

V. Percent distribution of live births by month of pregnancy prenatal care began, by legitimacy

status, and race: totrd of 33 reporting States and the District of Columbia, 1973 ......... ............... 26
SYMBOIX$

Data not available -------------------------------------- -..

category not applicable ----------------------------- . . .

Quantity zero ------------------------------------------ -

Quantity more than Obut less than 0.05---- 0.()

Figure does not meet standards of

reliability or precision -------------------------- *

I 1
CHARACTERISTICS OF BIRTHS

Linda Querec, M. A., and Emell Spratley, Division of Vital Statistics

INTRODUCTION

This report describes important characteristics of births occurring in the United States.

Much of the analysis was completed before 1974

and 1975 data became available. Therefore, data

for 1974 and 1975 are included in the next section, “Summary of PrincipaI Findings,” and

throughout the remainder of the report whenever trends are discussed. The major data in this

report, however, concern the characteristics of

births occurring in 1973.

Birth statistics presented in this report are

based on information obtained from the certificates of live birth filed throughout the United

States. Data for a number of the charactenstics–

educational attainment of parents, interval since

last live birth, interval since termination of last

pregnancy, outcome of last pregnancy, legitimacy status, month of pregnancy prenatal care

began, number of prenatal visits, and period of

gestation–are based on items that are not reported on the birth certificates of all States.

Because data on these characteristics are based

only on information for residents of reporting

States, caution should be used in extrapolating

these statistics for the United States as a whole.a

Moreover, there may be variations in a particular

statistic from one table to the next, depending

on the number of States in the reporting area for

which the statistic is computed. For example,

the incidence of low birth weight (2,500 grams

aAlthough legitimacy status was not reported on the

birth certificates for all States, national estimates of illegitimate births have been prepared on the basis of data

for the reporting States.

or less) was 7.6 percent for the entire United

States in 1973. The incidence was 7.3 percent

for the 41 areas which reported information

from which the interval since the last live birth

was derived, and 7.5 percent for the 43 areas

which reported month of pregnancy prenatal

care began. Table I in the appendix shows the

reporting areas for each of the characteristics

not reported by all States.

SUMMARY OF PRINCIPAL FINDINGS

In areas reporting education, the majority of

births occurred to mothers who had at least a

high school education. In 1973, these were 69.4

percent of all births; by 1975 this proportion increased to 71.4 percent. Infants born to mothers

with less than 12 years of schooling were more

likely to be of low birth weight (2,500 grams or

less) and to be premature (less than 37 weeks of

gestation) than were infants born to mothers

with more education. Moreover, these less educated mothers were less likely to receive prenatal care early in pregnancy and were more

likely to have an illegitimate birth than their

better educated counterparts.

The median birth weight for a.11infants

born in 1975 was 3,320 grams, or 7 pounds, 5

ounces. Seven percent of all newborns were of

low birth weight–that is, they weighed 2,500

grams (5 pounds, 8 ounces) or less. The median

birth weight of black infants was somewhat

lower than that of white infants, reflecting a

considerably higher incidence of low birth

weight among black infants than among white

infants-1 3.1 percent compared with 6.3 percent

1
in 1975. Failure by some investigators to eliminate the large racial differential after accounting

for differences in maternal ~haracteristics and

other factors known to be associated with low

birth weight suggests that genetic as well as environmental factors may be affecting the observed differences.

Premature births (born before 37 weeks of

gestation) comprised 9.2 percent of all live

births in reporting areas in 1973. There was a

large raciaI differential: 16.7 percent of black

babies compared with 7.7 percent of white

babies were classified as premature. In 1975, 8.9

percent of all live births were premature, and

most of the decline was among black infants.

In 1973, among States that reported the

month of pregnancy prenatal care began, nearly

71 percent of all births were to mothers who

started care during the first 3 months of pregnancy and only 1.5 percent of all births were to

mothers who received no care; there was little

change in these figures between 1973 and 1975.

For all mothers who received care and resided

in areas reporting this item, the median number

of prenatal visits per birth was 10.6. The comparable numbers for white and black births were

10.9 and 8.6 visits, respectively. By 1975, the

median number of prenatal visits had increased

to 10.8, and there was a larger increase for black

than for white births.

The sex ratio at birth varies little from year

to year; it was 1,054 mzde births per 1,000 female births in 1975.

Almost all (99 percent) infants born in the

United States during 1975 were classified aa

having been delivered by physicians in hospitals.

The gap between the proportion of white births

and black births occurring in hospitals continued

to narrow in 1975 —98.9 percent of white babies

compared with 98.0 percent of black babies.

In 1973, of 57,721 live births that occurred

in plural deliveries, the overwhelming majority

were twin deliveries. The multiple birth ratio

was 18.4 live births in multiple deliveries per

1,000 totaI live births. The ratio was 22.2 for

black births compared with 17.7 for white

births. In 1975 these ratios were slightly higher

(19.2 for all live births).

For all second and higher order births to

residents of States reporting the date of last

live birth, the mean interval since the last live

birth was 43.3 months in 1973. The mean interval since termination of the last pregnancy for

all births resulting from second and higher order

pregnancies was 40.4 months. This interval was

approximately l?12 years longer when the last

pregnancy ended in a Iive birth than when it

ended in a fetal death. By 1975, the interval

since last live birth had increased to 44.6 months

and the interval since termination of last pregnancy had increased to 41.4 months.

The estimated illegitimacy rate was 24.8

illegitimate births per 1,000 unmarcied women

aged 15-44 years in 1975, a decline from the

rate of 26.4 in 1970. In spite of the decline in

the rate, the illegitimacy ratio had increased

from 106.9 to 142.5 illegitimate births per

1,000 total live births between 1970 and 1975,

a result of both the decrease in marital fertility

and the increase in the number of unmarried

women.

EDUCATION

The educational attainment of both parents

was first tabulated in 1969. It is defined as the

number of years of school completed in public

or accredited private or parochial schools and is

useful as a measure of socioeconomic status. The

1973 data presented in this report were obtained

from 41 States and the District of Columbia.

Education of Mother

The proportion of births whose mothers

completed 12 or more years of schooI by age of

mother, live-birth order, and race is shown in

table 1. Mothers aged 15-19 years were more

likely to have less than 12 years of education

since most 15- and 16-year-olds have not yet

completed high schooL Of all births to mothers

in this age group, 19 percent were to 15- and 16-

year-old mothers who would very likely not yet

have had the opportunity to complete high

school. The proportion of births to mothers

completing high school rose with age to a peak

of 82.8 percent for the 25-29-year age group and

then declined to 58.9 percent for the oldest age

group. Similar age patterns were found for

both race groups. The percent of births to

2
nothers completing at least 12 years of school

vas higher among white births than among black

>irths for each age-of-mother group. The racial

iifferentia.1 was not as great among younger

~omen as among older women. For the 20-24-

,’ear age group, the proportion of births to

nothers who had completed 12 or more years

~f school was 19 percent higher among whites

than among blacks. This differential increased

with age to 77 percent for women aged 40 years

and over.

For each age-of-mother group the proportion of births to mothers with 12 or more years

of school tended to be inversely related to birth

order. For all ages combined, however, this proportion increased from 70.7 percent among first

births to 76.1 percent among second births, a

result of the fact that the distribution of births

by age is not the same for all birth-order groups.

For example, more than a third of first births

are to mothers aged 15-19 years, but only a

tenth of second births are to mothers in this

age group.

Between 1973 and 1975, the percent of all

births whose mothers had completed at least 12

years of school increased from 69.4 to 71.4 percent, reflecting an increase for both racial

groups.

The use of educationzd attainment of mother

as a measure of socioeconomic status in relation

to birth weight, period of gestation, prenatal

care, interval since last live birth, and illegitimacy are found in sections that follow.

Education of Father

TabIe 2 shows the percent distribution of

live births by educational attainment of father,

age of father, and race. Among all births, 75.9

percent were born to fathers with at least a high

school education. The age pattern of this proportion was identical to that for mothers.

A larger proportion of white than black infants were born to fathers with at least a high

school education (77.5 percent and 64.1 percent,

respectively). This was true for every age-offather category except that of 15-19 years where

the proportion was identical (48.6 percent) for

both white and black births. The racial differential was great est among infants b om to older

fathers.

A comparison with educational attainment

of mother (table 3) shows that a greater proportion of fathers than of mothers had compIeted

at least 12 years of schooling. Although the proportion who had completed just 12 years of

school was greater for mothers than for fathers,

this was more than offset by a much larger proportion of fathers than mothers who had compIeted 16 or more years of schooI.

BIRTH WEIGHT

An infant’s weight at birth has long been regarded as an indicator of his potential for survival and future growth. The greatest risks of

mortality and morbidity exist for those babies

who are of low birth weight. In 1975, 7.4 percent of all infants born were in this category.

Low birth weight is a function of intrauterine growth retardation as well as duration

of pregnancy. Statistics discussed in this section

make no distinction between low-birth-weight

infants who were born at term and those who

were born prematurely (before 37 weeks of

gestation). However, it has been pointed out

that with regard to postnatal care for the infant,

the distinction is of paramount importance,

since the care appropriate for low-birth-weight

infants who are premature may be inappropriate or even contraindicated for the full-term

low-birth-weight infant.1 Birth weight as it relates to duration of pregnancy is discussed at

greater length in the section, “Period of Gestation,” which follows.

Substantial differences between infants of

the two major racial groups in weight at birth

are well recognized. The median weight for

black infants was 220 grams or about 8 ounces

below the median weight for white infants in

1975 (table 4). Concomitantly, there was a considerably higher incidence of low birth weight

among black infants than among white infants

(13.1 percent compared with 6.3 percent) in

1975.

Some investigators have noted the persistence of this racial differential even after adjustments have been made for differences in such

maternal characteristics as age and parity, socioeconomic status, cigarette smoking,2 and prepregnant weight.3 Failure to eliminate the

3
Table A. Percent of live births of 2,500 grams or less by age of mother and live-birth order: United States, 1973

[See Technical Notes ]

Age of mother

Total .................................................................................................................

racial difference after accounting for these

factors known to be associated with birthweight differences suggests that genetic as well

as environmental factors may be affecting the

observed differences.

Information from a national study of

matched birth and infant death certificates for

the 1960 birth cohort shows that in each birthweight category below 2,001 grams white babies

have higher neonatal death rates than do babies

of all other races.4 )b This survival advantage at

lower birth weights supports the hypothesis that

infants of other races mature more rapidly at

these lower weights than do white infants. (See

the section, “Period of Gestation” for further

discussion of this hypothesis.) It appears that

the average birth weight of infants of races other

than white may be intrinsiczdly lower than that

of white infants, but a lower average birth

weight involves less risk for all other infants.

Still, among white and all other infants alike,

death rates are higher among those with low

birth weight than among heavier babies. At the

same time, many more infants of races other

than white are in the lighter categories. Therefore, as a population, all other infants are subject to higher average death rates. It has been

shown that elimination of the effects of birthweight distribution differences between white

bAs used throughout this report the term “all other”

refers to the combined grouping of all races other than

white.

Live-birth order

Total

1St 2d 3d 4th

7.6 7.6 6.8 7.5 8.2

15.8 14.9 37.2 ‘ -

10.0 9.0 12.5 16.9 19.3

7.2 6.6 6.6 9.1 11.3

6.3 6.4 5.4 6.2 7.6

6.9 8.3 6.1 6.1 6.6

8.4 11.1 8.2 7.6 7.9

9.1 13.3 10.1 8.6 9.4

9.7 20.6 9.8 10.3 6.1

5th

and

over

8.8

18,7

13.5

9.5

8.1

8.3

8.4

9.5

and all other births reduces much of the overall

observed mortality differentiaL4-6

There were no striking changes in the proportion of low-birth-weight infants in the period

from 1960 to 1975. This proportion increased

from 7.7 percent in 1960 to a high of 8.3 during the mid-1960’s and has since declined to a

level close to that of 1960 (7.4 percent in 1975).

The patterns of change in the level of low birth

weight among white and all other births during

this time were simiIar to that for total births.

Weight-at-birth data for black infants, available since 1969, have generally approximated

the levels observed for all other infants. In general, the incidence of Iow birth weight for black

births is slightly higher than that for all other

births. This is reflected in a somewhat lower

median birth weight for black infants.

Table 4 shows that there is a substantial difference in weight at birth according to the sex

of the child. Regardless of race, the median

weight of male infants is higher than that of

female infants. However, the median birth

weight for white females is higher th& that

of black infants of either sex.

Maternal age and live-birth order also are associated with variations in birth weight. The incidence of low birth weight is greatest among

mothers under 20 years of age, and to a lesser

extent among mothers in the later reproductive

years. Variations in the incidence of low birth

weight by age of mother are also related to the

birth-order distribution within each age group.

As can be seen from table A, high-order births

4
to young mothers and low-order births to older

mothers are subject to the highest incidence of

low birth weight. Birth weights are generaUy

most favorable when age of mother and birth

order are highly correlated.

Over the years, pIace of residence has persisted as a factor in variations in the leveIs of

low birth weight. Table 5 shows that the highest

levels of low birth weight occurred among babies

born to mothers residing in urban places with

populations of 10,000 or more within metropolitan counties, while the lowest levels were

among infants born to mothers residing in the

balance of these counties. This pattern holds for

all other births during recent years and for white

births in all years except 1975 when the percent

of low birth weight was higher in urban areas of

nonmetropoIitan counties. However, for the earlier years, the lowest incidence of low birth

weight among the all other group was for infants

born to mothers residing in the balance of nonmetropoIitan counties. In attempting to interpret

these statistics, it must be noted that a substantial proportion of all other births in the balance

of nonmetropolitan counties during the early to

mid-1960’s occurred outside of hospitak and,

therefore, probably lacked the more precise

measuring and reporting procedures available in

hospitals.

Education of Mother

The proportion of low-birth-weight infants

among those born to mothers with less than 12

years of education was 61 percent higher than

the comparable proportion among infants born

to mothers with 12 or more years of schooling

in 1973 (table 6). In general, for each age-ofmother group (with the exception of those at

the extremes of the childbearing ages) the proportion of low birth weight declined as educational attainment levels rose.

Among white births it can be seen that by

age of mother the IeveIs were 29 to 56 percent

higher among mothers who were not high school

graduates than among mothers with more education. Differences by educational attainment

were not as great for black births where, with

the exception of the 45-49-year age group, the

levels of low birth weight were 6 to 25 percent

higher among births to mothers who had Iess

than 12 years of schooling.

Although an increase in educational attainment was generally accompanied by a decline in

the proportion of low birth weight among white

as well as black babies, the racial differential in

these proportions generally widened as educatiorud attainment increased for both raciaI

groups (table 6). This indicates that increased

educational attainment is a more important

factor in the reduction of low birth weight

among white than among bIack babies. For

births to mothers with less than 12 years of

school, the level was 70 percent higher for black

babies than for white babies (14.8 compared

with 8.7 percent ). Among births to mothers who

were at least high school graduates, the difference was greater (the proportion among black

births was 111 percent higher than among white

births-1 1.8 compared with 5.6 percent).

The relationship between birth weight and

factors such as interval and outcome of last

pregnancy, legitimacy status, period of gestation, plurality, and prenatal care are discussed

in subsequent sections of this report.

PERIOD OF GESTATION

Period of gestation was determined from the

date of the mother’s last norrmd menstrual period

(LMP) as reported in 40 States and the District

of Columbia in 1973. The remaining States reported gestation in terms of weeks or months,

as determined by the physician’s estimate of

length of pregnancy. The result of this latter

method is often a substantial heaping at 40

weeks of gestation due to the tendency to assume that an infant of normal size has had a

gestation period of 40 weeks. The gestation

data presented in this report are based entireIy

on data from the IMP reporting areas since

these are assumed to be the more accurate gestation data.

From the percent distribution of births

shown in table B, it can be seen that a very

large majority of births occurred between 37

and 42 weeks of gestation. The proportion of

births classified as premature (born before 37

weeks of gestation) was more than 2 times as

great for black infants (16.7 percent) as for

white infants (7.7 percent).

The incidence of prematurity was highest

among infants born to mothers under 15 years

5
Table B. Percent distribution of live births by period of gestation end race: total of 40 reporting States and the District

of Columbia, 1973

[See Technical Notes ]

1 WE I

Period of gestation I II All

1 White Black

races

Total .............................. ........ 100,0 100.0 100.0

Under 20 weeks ................................ 0.0 0.0 0.1

20-27 weeks ...................................... 0.6 0.5 1.3

28-31 weeks ...................................... 1.1 0.8 2.2

32-35 weeks ..... ................................. 4.5 3.7 8.4

36 weeks ........................................... 3.0 2.7 4.7

37-39 walks ...................................... 35.5 34.4 40.0

40 weeks ........................................... 22.4 23.2 18.6

41J12 weeks ...................................... 24.5 26.0 17.3

43 weeks and over ............................. 8.4 8.6 7.4

llnc]udes races other than white and black.

of age (25.2 percent). It decreased to a Iow of

7.3 percent among infants born to mothers

aged 25-29 years, and then increased slowly to

11.5 percent among those born to mothers 40

years and over. The same pattern by age of

mother is seen for both major race groups (figure

1). The proportion of births that were classified as premature was higher among black than

among white births for all age-of-mother groups.

Birth weight is directly reIated to period of

gestation (see figure 2). Median birth weight increased with increasing gestation to 41-42 weeks

of gestation and then decreased sIightIy for 43

weeks or more. Of those births that were premature, 40.6 percent were also of low birth

weight while onIy 3.6 percent of fuII-term infants were of low birth weight.

Although black babies, in general, weigh less

at birth than do white babies, this was not true

for babies born at gestation intervals of less than

36 weeks. The median birth weight of black infants born at these shorter gestation intervals

was 80 grams higher than that of white infants;

at the longer gestation intervals, the median

weight of white infants was 190 grams higher

than that of black infants. This finding has

been corroborated by other investigators, some

of whom have hypothesized that at these early

40

All racesl

------- ~~i~e

‘-- Black

30

‘\.\

$ \,

; 20

“\

&

“\

‘., ‘\.

./” -

%, ./--

-.,

--\___ .— -—-- -

-. -_ %,

.-. -”-

%

‘.,

10

-------- .-------

0

U;Jer 15.19 20-24 2529 30.34 35.39 40 ancl

over

AGE OF MOTHER (IN YEARS)

NOTE A p,m,, u,e b,,,h ,, ..< that .,,.,, bcrorc 37 ,w.k, .( gc,t.,,on

llocludc, ,,<,, othm than wh, tc and black

Figure 1. Percent of live births premature by age of mother and race: total of 40 reporting States and the District of Columbia, 1973

6
4,(I2O

Whne

3,500 —

3,000

g

~

u 2,5W

z

=

&

g t

: 2,000

~

,8

a

z /

z 1,500

E

;

,4’

1,000 /

/

500

0

20 25 30 35 40 45

PERIODOFGESTATIONIIPJWEEKS)

Figure 2. Median birth weight by period of gestation and race:

total of 40 reporting states and the District of Columbia,

1973

gestation intervals the black fetus matures more

rapidly.’

Between 1973 and 1975, there was a decline in the percent of births that were premature, from 9.2 to 8.9 percent. Although most

of this was due to the decline in prematurity

among black births, the large racial difference remained.

Education of Mother

As shown in table C, premature births were

more likely to occur to mothers with fewer

years of education than to mothers who had

completed 12 or more years of education. A premature birth was more than twice as likely to

occur to a mother who had less than a high

school education than to a mother with a college

degree. The lower education categories are more

heavily weighted with mothers from the lowest

and highest age groups who are themselves more

prone to give birth prematurely than are women

of the intermediate childbearing ages.

Table C. Percent of live births premature by race and educational attainment of mother: total of 37 reporting States

and the District of Columbia, 1973

[See Technical Notes ]

Years of school completad All

by mother 1 White Black

races

Total ......................................

o-8 years ...........................................

9-11 years ....................... ..................

12 years ............................................

13-15 years .......................................

16 years or more ......... ............... .......nrr 9.3 7.8 16.9

13.6 11.5 21.0

12.9 10.4 19.6

8.3 7.2 15.0

7.1 6.3 13.3

5.8 5.4 10.5

Less than 12 years ............................. 13.1 10.7 19.8

12 years or more ............................... 7.7 6.7 14.4

1Includes races other than white and black.

NOTE: A premature birth ia one that occurs before 37

weeks of gestation.

There appears to be no appreciable reduction

in the racial differentizd in the percent premature among births to mothers of similar socioeconomic status. Overall, this percent was 2.2

times as great among black as among white

births; among births to mothers with 12 or more

years of schooling and with less than 12 years,

the percent was 2.1 and 1.9 times as great,

respectively.

MONTH OF PREGNANCY PRENATAL

CARE BEGAN

Adequate care received during pregnancy is

generally accepted as a relevant factor in the reduction of pediatric and obstetric problems such

as low birth weight, congenital anomalies, fetal

and neonatal mortality, and maternal mortality.

Since early care is highly correlated with

more care and the detection of obstetrical problems during early gestation stages can possibly

avert certain adverse pregnancy outcomes, early

pregnancy is generally held to be the optimum

time for initiating prenatal care.

In 1973, the month of pregnancy prenatal

care began was reported on the birth certificates

of 42 States and the District of Columbia. For

these areas, the largest proportion of all infants

(43.8 percent) were born to mothers who began

care in the first 2 months of pregnancy. Nearly

7
60

Whine

40 \

20

0

Under 1519 2024 25.29 30.34 35.39 4044 45.49

15

AGE OF MOTHER (IN YEARS)

J 1, Ifxlm(

40 r, -

~?c’”,

Black

-------- .-------

------- --------

---.-+

20

n

1* 2nd 3rd 4th 5th 6th

b,nhs births b,rths births births b,rth$

and

LIVE. BIRTH OROER over

Figure 3. Percent of births to mothers beginning prenatal care during the first 2 months of pregnancy, by age of mother and race and

live-birth order and race: total of 42 reporting States and the District of Columbia, 1973

71 percent of all infants were born to mothers

who initiated care during the first 3 months of

pregnancy and only 1.5 percent of all infants

were born to mothers who received no care

(table 7). By 1975, there had been only slight

changes in these figures-72 percent of all

mothers began care in the first trimester and 1.3

percent received no care.

Examination of the distribution of births by

the month of pregnancy prenatal care began for

the two major race groups shows that there was

a substantial difference between the groups with

regard to the proportion of births to mothers

who started care in the first 2 months of pregnancy-47. 1 percent of white births compared

with 28.2 percent of black births. Moreover, the

proportion of black births to mothers who began care in the last 3 months of pregnancy was

more than twice the comparable proportion of

white births (table 7).

In addition to the greater delay by mothers

of black births in obtaining prenatal care, the

total lack of prenatal care was higher for this

group as well. The proportion of mothers with

no prenatal care for black births was slightly

more than 3 times that observed for white

births–3.4 percent as compared with 1.1 percent.

Table 7 shows that age of mother is an important factor associated with the time of initiating prenatal care. For all infants, the proportion of births to mothers initiating care

during the first 2 months of pregnancy increased with age of mother through the group

aged 25-29 years; over half (52.5 percent) of

the births to women in this age group were to

those who initiated care at this time. For women 30 years of age and over, as age increased there was a J~eady decline in the proportion

of births to women who started care early. Very

young mothers experienced the highest percent

of no prenatal care, and, to a lesser extent, so

did mothers at the older reproductive ages.

These patterns of initiation of prenatal care according to age of mother were similar for both

major race groups (figure 3).

As can be seen from table 8, for each birth

order after the second there was a steady decline

in the proportion of births to mothers who

started care during the first 2 months of pregnancy. While there was a considerable difference

between white and black mothers in tjhe time of

initiating prenatal care, both groups tended to

delay care as parity increased (figure 3). Moreover, as parity increased, there was a generally

higher percent of mothers reporting no prenatal care. It has been suggested that this is

possibly the result of increasing home responsi

bilities and perhaps greater demand on limited

financial resources.8 ““

Percent Low Birth Weight

Among all resident births in States reporting

month of pregnancy prenatal care began, the incidence of low birth weight was lowest when

8
mothers initiated care during the first 2 months

of pregnancy (6.4 percent). (See table D.) Levels

of Ioy birth weight incrqwed as initiation of

prenatal care was delayed until the 6th month

(9.2 percent) then decre=ed for mothers beginning care in the last 2 months of pregnancy

(about 8.0 percent). The pattern for white

births was the same as for total births. Although

there was no consistent pattern among black

births, the lowest levels of low birth weight for

this group were among births to mothers who

started care in the last 2 months of pregnancy.

There are large differences in the proportion

of low-birth-weight babies born to mothers who

received some care and to mothers who received

no care. The percentage of low-birth-weight infants born to mothers who had received some

care was 7.2 as compared with 21.1 percent for

mothers who had received no care. Examination

of gestation data for mothers who had received

some care and mothers who had received no care

(available for the 39 States and the District of

CoIumbia which reported b, ~,h date of last

normal menses and month o1 pregnancy prenatal care began) shows that a large proportion

of infants in the no-care group were born prior

to 37 weeks of gestation. Slightly more than onequarter (26.1 percent) of all births to mothers

receiving no care occurred at gestation ages of

less than 37 weeks, compared with 8.9 percent

of births to mothers receiving some care. For the

Table D. Percent of live births of 2,500 grams or less for each

month of pregnancy prenatal care began, by race: total of

42 reporting States and the District of Columbia, 1973

[See TechnicaI Notes]

Month of pregnancy prenatal

I

All

care began races1

LWhite

Total ......................................

[/

7.5 6.4

“lW2d-month .................................... 6.4 5.8

Bd month ....................................j.ty. 7.0 6.1

4th month ......................................~-~. 8.4 6.9

5th month ......................................... 9.0 7.3

6th month ... .................... .................. 9.2 7.5

7th month .................................... ..... 9.0 7.1

8th month ........................... .............. 8.0 6.7

9th month .................................. ....... 8.1 7.0

No prenatal care ...................... .......... 21.1 17.5

Black

13.3

12.0

12.4

13.4

13.1

13.1

13.4

11.9

11.3

27.4

lInclude~ races other than white and black.

two major racial groups the percent of births

that were born at less than 37 weeks of gestation are shown below.

White Black

Some care ..................................... 7.6 16.3

No care ................. ........ ...... ..... . .... 22.2 31.2

It has been noted that the “no-care” category is

likely to include mothers who would have obtained some care had not the early birth of the

child intervened.g

Education of Mother

As can be seen from table 9, earlier prenatal

care is associated with increased levels of educational attainment. When births are examined

with regard to those born to mothers who received less than 12 years of education and to

mothers who were at least high school graduates,

considerable differences can be seen. The proportion of births to mothers who began care in

the first 2 months of pregnancy was 69 percent

higher for mothers who were at least high school

graduates than for mothers who were not. The

proportion of births to mothers who had no care

was 2.6 percent for those who completed less

than 12 years of school compared with 0.7 percent for those with 12 or more years of school.

A similar association was evident among

white and black births, although differences in

the time of initiation of care according to educational attainment were generally greater for

white mothers. This was particularly true for

care initiated during the second and third trimesters and for no prenatal care. The proportions of births to white mothers beginning care

in the last two trimesters amd to mothers with

no care were nearly 2 to 5 times as great for

those who had less than 12 years of school; the

comparable proportions for black births were

less than twice as great.

The proportion of births to mothers beginning care in the first 2 months of pregnancy was

higher among white than among black births

(1.7 times as great). The racial difference was

reduced appreciably only among births to

mothers with 16 or more years of school where

the proportion for white births was 1.2 times

that for black births. When these proportions

9
are considered for births to mothers with less

than 12 years of school as opposed to mothers

who were at least high school graduates, the

racial difference is the same (1.6 times as great

for white births).

There were greater variations in racial differences according to education of mother for

mothers who began care in the last 2 trimesters

of pregnancy and for mothers who had no care.

Among births to mothers with less than 12

years of school, these proportions were 1.4 to

2.4 times as great. These differences widened

to 2.1 to 5.8 times as great among births to

mothers with 12 or more years of school.

NUMBER OF PRENATAL VISITS

Another measure of prenatal care, available from the birth certificates of 38 States

and the District of Columbia in 1973, is the

number of visits for prenatal care made by the

mother. The median number of prenatal visits

per birth for all mothers residing in these areas

who received some care was 10.6. The comparable figures for visits made by white and

black mothers were 10.9 and 8.6, respectively

(table 7).

The median number of prenatal visits was

highly correlated with the month of pregnancy

prenatal care began in the 38 areas that reported

both items. The median number of prenatal

visits declined as initiation of care was delayed,

as can be seen from table E. The relative difference between the median number of visits for

white and black mothers was greater for the

total than for any individual month in which

care began. Therefore, much of the racial differential in the totaJ median number of visits

can be attributed to the fact that white mothers

began care earlier than did black mothers.

Differences in the median number of visits

by age of mother and by live-birth order (tables

7 and 8) are also related to the differences in

the time of initiating care. The increase in the

median number of visits with increase in age for

mothers under age 30 is associated with the fact

that these mothers started care earlier as age increased. The slight but steady decline in the

median number of visits per birth as age adTable E. Median number of prenatal visits, by month of pregnancy prenatal care began and race: total of 37 reporting

States and the District of Columbia, 1973

[See Technical Notes ]

Month of pregnancy prenatal

care began

Total ......................................

Ist month ............ .............................

2d month ..........................................

3d month ... .................... ...................

4th month ............................... ..........

5th month ............................ .............

6th month .........................................

7th month ...................................... ...

8th month .........................................

9th month .........................................

4P*

It

10.6 10.9 8.6

12.6 12.7 11.8

12.1 12.2 10.7

10.7 10.8 9.8

9.2 9.5 8.2

7.8 8.2 7.0

6.5 6.9 5.9

5.4 5.7 4.8

4.0 4.2 3.6

2.6 2.7 2.3

lIn~l~des races other than white and black.

vanced for mothers 30 years of age and over is

also related to patterns of prenatal care initiation for these women. In addition, for aIl

births after the second, there was a decline in

the median number of visits as birth order increased. This is related to the decline in the

proportion of births to mothers starting care

early for each birth order after the second.

These relationships by age of mother and birth

order were generally true for both major race

groups.

By 1975, the median number of prenataI

visits had increased to 10.8; there was a larger

increase for black than for white mothers (9. 1

and 11.1 visits, respectively, in 1975).

Percent Low Birth Weight

Variations in proportions of low-birthweight babies according to the amount of prenataI care received by the mother are shown in

table F. The proportion of low-birth-weight infants declined as the amount of care increased

from no visits to 13 and 14 visits. The pr~po=

tion then rose somewhat for visit levels above 14.

It has been suggested that the logical nature

...

of the relationship between prenatal care and

the levels of low birth weight is not as direct as

casual examination of the data would indicate. 10 The association may be a secondary one

since factors known to be associated with low

10
Table F. Percent of live births of 2,500 grams or less by number as the educational attainment level advanced

of prenatal visits and race: total of 38 reporting States and

the District of Columbia, 1973 from 12 years to 16 years or more.

[See Techni@$

Number of prenatal visits

Total visits ..............................

No visits ............................................

1-2 visits ............................................

3-4 visits ............................................

5-6 visits .............. ..............................

7-8 visits .................................... ........

9-10 visits ..........................................

11-12 visits ................... ........ .............

13-14 visits ........................................

15-16 visits ................................. .... ...

17-18 visits ........................................

19 visits or more ......................... ......

,tes ]

All White

racesl

7.5 6.3

22.5 19.5

21.7 19.8

18.2 17.3

13.8 13.5

9.4 8.8

6.0 5.4

3.9 3.5

3.3 2.9

4.0 3.5

3.8 3.3

6.3 5.5

Black

13.3

-

26.6

25.1

20.3

15.0

11.8

9.5

7.5

6.6

8.3

7.5

10.5

1Includes races other than white and black.

birth weight (such as socioeconomic status, age

of mother, and parity) also infl~uence the receipt

of prenatal care. 1

Education of Mother

The median number of prenatal visits rose

as the level of educational attainment increased

for white mothers as well as for black mothers

as shown in table G. While the relative difference between the races in the median number

of visits was the same for mothers who completed less than 12 years of school as it was for

all mothers, this difference nearly disappeared

Tabla G. M;dian number of prenatal visits by educational attainment of mother and race: total of 37 reporting States and

the District of Columbia, I!373

[See Technical Notes ]

Years of school completed

by mother

Total ...................................{+1

O-B years ......................... ..............+..-.

9-11 years .............. ...........................

12 years ....................................... .....

13-15 years .......................................

16 years or more ...............................

-n- All

racesl Whita

10.5

8.4

9.3

10.8

11.4

11.6

l~ncludes ~ace5 other than white and black.

10.9

8.9

9.9

11.1

11.5

11.7

Black

8.6

7.0

7.8

9.1

10.0

11.2

SEX RATIO OF BIRTHS

In 1975, the sex ratio of live births was

1,054 males per 1,000 females. It has varied

little from year to year from 1940 to 1975,

ranging from 1,047 to 1,059.

It has been estimated that the primary sex

ratio (defined as the ratio of males per 1,000

females at the moment of conception), has a

minimum value of 1,10011 and may be as high

as 1,600.12 The sex ratio of fetal deaths of 20

weeks or more gestation (1,126 in 1973) is

higher than that of live births. A higher ratio

for earIy fetaI deaths (20-27 weeks) than for late

fetal deaths (28 weeks or more) implies an even

higher sex ratio for fetal deaths of less than 20

weeks of gestation. These high ratios for fetal

deaths result in a lower sex ratio at birth than at

conception.

The sex ratio varies widely by race as indicated by the average sex ratio for the years

1970-73 as shown in table H. The ratio ranged

from 1,080 for Filipino births to 1,020 for

American Indian births. The ratios for the two

major race groups were 1,058 for white births

and 1,028 for black births. The ratio for each

of these two groups varied Iittle from year to

year and was consistently higher for white than

for black births.

As shown in table J, the sex ratio was higher

among single than among plural deliveries. One

Table H. Sex ratio by race: United States, 4-year averaga,

1970-73

Race

I Males

per

1,000

females

All races............................................................

1=

1,053

White ...................... .............. ....................................... 1,058

Black ......................................... ................................. . 1,028

American Indian ............................ .............................. 1,020

Chinese ........................................................................ 1,069

Japanese ................. .............................................. ....... 1,048

Filipino ........................................................................ 1,OBO

Other ......................... .................................................. 1,059

11
Table J. Sex ratio at birth by race and plurality: United States, 1971-75

[See Technical Notes ]

Race and plurallty

I

1975

I 1’73 I ‘E@

llnclude~ races other than white and black.

possible causal factor is the higher sex ratio of

fetal deaths in plural pregnancies compared to

single pregnancies (1 ,197 and 1,121, respectively,

in 1973).

In general, the sex ratio was inversely related

to birth order and age of mother (table K). However, when these two variables were crosscIassified, no consistent pattern emerged by

birth order or age of mother. Previous studies

showed that birth order has a definite effect on

sex ratio at birth; the maternal-age effect, however, results from the correlation between birth

order and age of mother. 12>13

1’ Males per 1,000 females

1,054 1,055 1,052 1,051 1,052

1,055 1,056 1,053 1,052 1,053

1,005 1,007 999 1,016 1,014

1,059 1,059 1,057 1,057 1,056

1,059 1,060 1,058 1/058 1,057

1,018 1,011 1,005 1,018 1,022

1,030 1,030 1,028 1,024 1,028

1,032 1,031 1,030 1,025 1,029

965 982 972 1,000 992

Although the sex ratio varies little on a

yearly basis, it varies a great deal from month to

month, especiall~ among black births. For example, during 1973 the sex ratio for black births

ranged from 1,000 in March to 1,055 in October.

The sex ratio for white births ranged from 1,044

in September to 1,067 in November. Figure 4

shows an average of the sex ratio by month for

white and black births for the years 1970-73.

Although a large variation exists, no seasonal

pattern can be identified. These figures show

that the ratio was always higher for white than

for black births.

Table K. Sex ratio at birth by live-birth order and age of mother: United States, 1973

[See Technical Notes ]

Age of mother

Totall ............................... .................................................

15-19 years ...................................... .............. ........................ .............

20-24 years .................................................................................. .......

25-29 years ...................................................................................... ...

30-34 years ................................................................ .........................

35-39 years ............................................ .............................................

4044 years .........................................................................................

lInclude~ births to women under age 15 and age 4S and over.

2Rati~ based on fewer than 1,000 births..

II Live-birth order

Total 6th

1St 2d ‘d 4th 5th and

over

,..

1,052 1,051

1,055 1,056

1,055 1,059

1,046 1,075

1,041 1,053

1,021 21 ,.f23

‘a’es‘er”‘(!.OO

T

1,059 9;&9

1,059 ;;002

1,058 1,053

1,060 1,054

1,066 1,043

1,058 1,037

990 1,079

..l.

!males 9

IT1,036 1,026 1,030

21,128 2975 21,087

1,051 994 1,036

1,034 1,031 1,054

1,021 1,031 1,023

1,067 1,034 1,020

961 1,001 1,023

12
rwi

1,070 *

Averagefor the

\

4.year period

1,s.s0

... ....... ----- ------ ----------- .---- ?

1,050 -

/

---------

!,

,/

1,C40 t

%

/

‘%,

,/ ‘\

\, 0 ‘

,4’ ‘\,

/

Averagefor the

\

‘\\ ,8’ ‘\

1,030 .- ●

4.vear period

*

--------- >/f ---- -------- --------- -------+,; ---------- -/~------ ----y --*-- --------

‘*, Black

,-------

t

\\ d

..-

1,020 ‘8. . . .

7

/

/

‘%

%

%

1010

1

0 .

Jan. Feb. Mar, ,~ Apr. May June Ally Aug. Sept. Oct. Nov. Dec.

MONTHOFBIRTH

.

Figure4. Sexratio bymonth of birth and race: United States, 4-year average, 1970-73

MONTH OF BIRTH

The monthly indexes of births occurring in

the United States during 1960, 1970, 1973,

and 1975 are shown in table L. These indexes

are the ratios of the actual number of births in

a month to the average monthly number for the

calendar year multiplied by 100 and adjusted for

the varying number of days in each month.

In 1975, the monthly indexes showed minor

peaks in February and December, and a major

one in September. Indexes for 1960 showed a

more prominent peak for September and a

deeper trough for the spring months than was

exhibited for more recent years. The reduction

in the degree of seasonali$y can be seen in the

decline of the standard deviation of the monthly

indexes. In 1975, the st~drard deviation was 3.3

compared with 5.8 in 1960.

The distribution of births by month of occurrence tends to be bimodal in the United

States, but there are variations in the amplitude

of the seasonaI curve by- race and by region.

Figure 5 shows the variations by race in the

Table L. Monthly indexes of live births and standard deviations:

United States, 1960, 1970, 1973, and 1975

[See Technical Notes ]

Month of occurrence 1975

I

1973 1970 1960

I

Monthly indexes

Total .........................

January ............. .... ..............

February .............................

March ..................................

April ....................................

May .....................................

June ....................................

July .....................................

August .................................

September ...........................

October ............................. ..

November ............................

December ............................

100.0

97.1

98.7

98.0

97.1

98.0

99.0

104.8

104.8

105.9

100.3

96.7

99.5

100.0

99.8

100.2

100.9

96.0

95.5

98.6

103.3

105.6

105.0

99.6

97.7

97.8

I

Standard

100.0

95.3

98.2

96.9

93.5

93.9

98.7

104.1

104.4

108.2

102.2

100.8

103.8

wiation

100.0

95.8

97.7

97.0

93.8

92.4

95.3

103.8

108.8

111.0

102.7

100.2

101.4

Total ......................... 3.3 3.3 4.7 I

5.8

NOTE: Index is the ratio of the actual number of births in a

month to the average monthly number for the year multiplied

by 100. Adjustment has been made for the varying number of

days per month.

13
115

UNITED STATES NORTHEAST NORTH CENTRAL SOUTH WEST

l!llllll illlllllll 111111~111111 1111111 11111111 llllllllllll

110

105

90

85

0 J—u—l—u

MONTH OF OCCURRENCE

(Rat,o of number of broths m the month to the average monthly number for the yew multiplied

by 100. Adjustment has been made for varying number of days per month. )

Figure 5. Monthly indexes of live births, by race: United States and each region, 1973

seasonal patterns for the four geographic regions in 1973, using the monthly index. In all

four regions the distribution of black births by

month shows greater variation, as evidenced by

more prominent peaks and deeper troughs, than

does that of white births. The standard deviations for both groups in each of these, regions in

1973 are shown below.

White Black

Northeast ...................................... 3.0 3.5

North Central ................................ 3.5 4.6

South ............................................ 4.1 8.0

West .............................................. 2.9 3.8

The seasonal patterns for white and black

births resembled each other in shape in all regions except the West where the seasonality of

white and black births differed considerably during the first half of the year.

ATTENDANT AT BIRTH AND

PLACE OF DELlVERY

The vast majority of live births occurring in

the United States are delivered in hospitals. Of

all live births delivered in 1975, 98,7 percent

were classified as having been deIivered by ph ysicians in hospitals. These deliveries included all

live births occurring in hospitals or other institutions and births attended by physicians in clinics.

The gap between the proportion of white

births and all other births occurring in hospitals

continued to narrow in 1975 (figure 6). Comparison of the two major racial groups shows

that 98.9 percent of white births and 98.0 percent of black births were delivered by physicians

in hospitals.

Over the years, the increase in hospital

utilization for obstetrical care has resulted in a

decline in the proportion of births occurring

14
100

95

90

85

80

0

1 -white ------ ,------ ------

#.~ --*. - ------

**H

,4*

,/”

~~-.

e-

*. *- “

~.

1 i I I I I I 1 I I I I , I

1960 1962 1964 1966 1968 1970 1972 1974 1975

YEAR

, Figure 6. Percent of live births occurring in hospitals, by color: United States, 1960-75

I

outside these facilities. Physicians outside of

hospitals delivered only 0.4 percent of all live

births in 1975. The comparable proportions for

white and black births were 0.3 and 0.6 percent,

respectively. The proportions of midwife-attended births are also at relatively low levels–O.4

percent of all births, 0.2 percent of white

births, and 1.0 percent of black births in 1975

(table 10). —

Much of the differential that has existed between the rates of hospital utilization for white

and all other births could be attributed to differences among all other births by place of

residence. In 1960, 99.1 percent of white births

and 94.5 percent of all other births in urban

places with populations of 10,000 or more were

delivered by physicians in hospitals. In contrast,

during the same year, 98.3 percent of white

births and only 68.0 percent of births of aII

other races in the balance of the country were

delivered by physicians in hospitak. However,

place of residence has assumed diminishing importance as a factor in the distribution of all

other births by attendant. In 1975, 98.8 percent

of all other births in urban places of 10,000

residents or more were delivered in hospitals,

compared with 96.3 Percent of all other births

in th”ebalance of the c-ountry.

Rates of utilization of midwives as attendants

for all other births have also varied a great deal

by type of residence and geographic division,

and while fairly substantial differences still

exist, there have been large declines for all areas.

As can be seen from table 10, for the balance

of the country the proportion of births of all

other races delivered by midwives declined

from 25.7 percent in 1960 to 2.3 percent in

1975. The comparable proportions for urban

areas of 10,000 residents or more were 2.8 in

1960 and 0.3 in 1975. The proportion of all

other births attended by midwives is highest in

the East South CentraI Division where, in 1973,

4.7 percent of all other births were delivered

by midwives. As recently as 1967, the proportion was as high as 21.8 percent.

Comparisons of the two major raciaI groups

with regard to differences by place of residence

are not possible before 1969; data on black

births by attendant are available only for 1969

and later years. However, distributions of black

15
births for more recent years have been very

similar to the distribution for all other births.

Geographic variations in the proportion of

births occurring in hospitals are somewhat

greater for black births than for white births

(table 11). During 1973, in all divisions except

the West South Central over 99 percent of white

births occurred in hospitals. The proportion of

black births occurring in hospitak was over 99

percent in six of the nine geographic divisions.

In the three divisions of the South Region, rates

of hospital utilization for blacks ranged from

94.6 percent (East South Central) to 98.3 percent (West South CentraI).

MULTIPLE BIRTHS

Of the 57,721 live births that occurred in

multiple deliveries in 1973, the overwhelming

majority were twin births (98.4 percent ). The

multiple birth ratio is the ratio of live births in

multiple deliveries per 1,000 total live births.

This ratio has decreased only slightly since the

earIy 1960’s, from 20.4 in 1960 to 18.4 in 1973.

In 1975, the ratio was 19.2.

As in other years, black mothers were more

likely than white mothers to have a multiple

birth. The multiple birth ratios in 1973 were

22.2 for black mothers and 17.7 for white

mothers (table M).

Table M. Ratio of plural live births to total live births by age of

mother and race: United States, 1973

[See Technical Notea ]

Age of mother All

White Black racesl

Plural births per

1,000 live births

Tota12 .................................... 18.4 17.7 22.2

15-19 years ....................................... 12.1 11.1 14.7

20-24 years ............................... ........ 16.8 15.7 22.8

25-29 years ....................................... 21.0 20.2 28.8

30-34 years ....................................... 24.5 23.6 32.0

35-39 years ....................................... 26.2 25.2 32.8

4044 years ............................... ...... .. 21.8 21.6 23.6

l~nclude~ ~ac= other than white and black.

21nc1ude~ births to women under age 15 and age 45 and over.

The proportion of multiple births increased

as age of mother increased through the 35-39-

year age group and then decreased slightly for

mothers aged 40 years and over. In fact, for

both the white and black population the chances

of a 35-39-year-old mother having a. multiple

birth in 1973 were over twice as great as for a

15-1 9-year-old mother.

Both white and black births occurring in

plural deliveries have a shorter gestation period

and are of lower birth weight than m-e births

occurring in single deliveries. Of single white

births, 7.2 percent were classified as premature

(gestational age of less than 37 weeks) as opposed to 38.0 percent of phud white births.

Comparable proportions for black births were

16.1 and 45.0 percent, respectively. A premature infant is more likely to be a low-birthweight infant and, since a large proportion of

multiple births are premature, it follows that

a large proportion are of low birth weight. Of

those white infants in multiple deliveries, 52.6

percent were of low~b~th weight, more thqn 9

times the proportion ~f white infants in sip#q

vihiz

Table N. Median birth weight and percent of live births of 2,500

grams or less, by plurality and race: United States, 1973

[See Technical Notes]

Race

rl

All races ........................................... .....

White ...............................................................

All other ..................................... .....................

Black ..........................................................

Plurality

=1=

Median

birth weight

in gramsl

3,3:10 I 2,430

I

3,360 2,460

3,160 2,290

3,150 2,280

PercBnt of live

births of 2,500

grams or less

‘t

6,,7 54.8

5.6 52.6

11.4 63.1

12.1 63.9

lcomPuted to nearest 10 gS’aItMOfl eXaCt conversion‘f ‘nterval limits from pounds and ounces.

16
deliveries (5.6 percent), as shown in table N.

Low-birth-weight infants also were predominant

among black infants born in plural deliveries

(63.9 percent). Of black infants in single deliveries, only 12.1 percent weighed 2,500 grams or

less. The median weight of infants in single

deliveries was 3,330 grams compared with

2,430 grams for infants in plural deliveries, a

difference of about 2 pounds.

INTERVAL SINCE LAST LIVE BIRTH

The item “date of last live birth” was added

to the U.S. Standard Certificate of Live Birth to

provide information on child spacing. The information provided by this item makes it possibIe to compute intervals between successive

births, which is valuable in health and fertility

research.

In 1973, the date of last live birth was reported on the birth certificates of 40 States and

the District of CoIumbia. This item was used to

coihpute the interwd sii-k!e Iast live birth for aII

second and higher order births to mothers residing in these areas.

The mean interval since the last live birth for

all second and higher’ order births was 43.3

months. Table O shows that the length of this

interval was similar for white (43.6 months) and

black (42.4 months) births. Between 1973 and

1975, the mean interval increased 1.0 month for

white births and 2.7 months for black births. As

a result, in 1975 the direction of the racial difference was reversed; the mean interval was 44.6

months for white births compared with 45.1

months fo~ black births.

Examination of the mean interval since the

previous live birth according to birth order

shows that the interval was shortest for second

births (39.2 months), increased with birth order

through fifth births (51.2 months), and then decIined through the eighth and higher orders. This

pattern was the same for white births as for total

births but varied slightly for black births where

the mean interval increased through the seventh

birth order and then declined for eighth and

higher orders. These patterns remained the same

through 1975. In 1973, the differences between

the two major racial groups in the mean interval

since the last live birth for a second and seventh

Table O. Mean intewal since last live birth, by live-birth order,

age of mother, and race: total of 40 reporting States and

the District of Columbia, 1973

[See Technical Notes]

Live-hi rth order and

age of mother

All second and higher

order births ..........................

LWe-biflh order

Second births ....................................

Third births .......................................

Fourth births .....................................

Fifth births ........................................

Sixth births ...................... .................

Seventh births ................. ..................

Eighth births and over .......................

Age of mother

Under 15years .................... ..............

15-19 years ............ ............................

20-24 years ............................ ............

25-29 years .................... .. ...... ............

30-34 years ...... ...... ............................

35-39 years ............ ............................

40-44 years ................ ............ ............

4549 years ........................................

ZIEIEi

Mean interval in

months

-1

43.3 43.6

39.2 39.2

46.5 47.3

49.6 50.7

51.2 52.6

49.8 51.0

48.4 49.1

42.6 42.9

20.7 29.1

21.9 21.7

31.8 31.7

42.7 42.3

57.0 56.7

L

73.7 74.6

86.6 88.1

101.5 105.5

42.4

-

39.8

43.0

44.9

46.4

46.8

47.2

42.6

16.4

22.3

32.8

47.8

61.9

72.0

81.0

86.9

1Includes races other than white and black.

and higher order births were less than 2 months.

For the remainder of the birth orders, however,

the mean intervals were 4 to 6 months longer for

white births than for black births.

The mean interval since last live birth generally increased with age of mother in both major

racial groups. During 1973, for mothers aged 15-

34 years these intervals were up to 6 months

longer for black births than for white births. At

the remaining age groups, the mean intervals

were 3 to 19 months longer for white births.

At the younger ages, racial differences in

interval since last live birth may reflect a greater

incidence of induced abortion among black

women than among white women. For even

though black women are more likely to be noncontraceptors, the length of their birth intervals

is somewhat longer, as mentioned above. According to estimates of numbers of legal abortions in the United States during the period

17
1972-74,14 the abortion ratio for women of

races other than white was 1.5 times as great as

the ratio for white women. At ages 20-34 years,

the ratios were 1.6 to 2.5 times as great for

women of races other than white.

On the other hand, at ages 35 and above a

more important factor in the racial difference

may be the higher proportion of noncontraceptors among black women. There is not as

much difference between abortion ratios for

white and all other women at older ages (0.9

to 1.4) as at the ages mentioned above. In addition, information from the National Survey

of Family Growth15 indicates that 32.4 percent

of currently married white women 35-44 years

of age compared with 48.2 percent of their

black counterparts were noncontraceptors in

1973. This difference in the use of contraceptives was not as great for younger women

and in addition to the abortion clifferences

mentioned above may explain, in part, the reversal in the direction of the differential.

Between 1973 and 1975, the increases in

the interval since the last live birth were greater

for black births than for white births of all birth

orders and for mothers in all age groups. Although the direction of the racial difference

remained the same for most birth orders and age

groups, it reversed for seventh and higher order

births and for mothers under 15, and 35-39

years of age. In 1975, the intervals for these

groups were longer for black births than for

white births, but in 1973 they were longer for

white births.

When the mean interval since the previous

live birth is examined by birth order in conjunc45.49 years

P<

/

\

$lJ1.

1,

\

.

40.44 years

--#-- “----------- -.. ‘\

---- -----

--z- ---

---

%, x

3539 years

%%

%

/“ ‘ -\_

%

%

//’ \

% -

----- ,

\\

\ ------

\ %,

‘1, %,

30-34 years *. \ %

../- --\. _ --- ----

/-- --\___ %

-

---- ‘\\

---

2529 years . +.- \

---------- -.. .

---- ----

------- ~- -

-+.

. . . . . . . . . . . . . . . . . . . . 20.24 years

-------- ~

o

2d 3d 4th 5th 6th 7th 8th

b,rths b,rths bmhs births births births births

and

LIVE BIRTH ORDER over

Figure 7. Mean interval since last live birth, by age of mother and live-birth order: total of 40 reporting States and the District of

Columbia, 1973

18
tion with age of mother, as in figure 7, it can be

seen that for each birth order the length of the

interval generally increased with age of mother.

For mothers 25 years of age and over, the length

of the interval decreased as parity increased after

the third birth. For mothers 20-24 years of age,

the length of interval decreased from the second

to seventh order, then increased for eighth and

higher orders.

Education of Mother

The relationship between the mean interval

since last live birth and educational attainment

of the mother is different for white than for

black births (table 12). With increasing years of

school completed from 12 to 16 or more, the

mean interval for white births decreased; for

black births, it increased. This was true for all

birth orders.

Spacing has been identified as an important

factor associated with fetal and infant mortality

rates. These rates have been found to be lowest

when the interval between two pregnancies is beL

ween 2 and 3 years, and the highest infant

ortality rates occur when the birth interval

is less than 2 years. 16 Nearly 40 percent of all

low-birth-weight infants compared with sIightly

more than one-fourth of heavier babies in the

States reporting date of last live birth wert born

less than 2 years after a previous birth.

The relatively high incidence of low-birthweight infants among young mothers of high

parity suggests that the interval between births

may be a factor associated--with low birth

weight. Data in table 13 show that the incidence

of 10w birth weight for each age group was

highest among births that occurred less than a

year after a previous birth. On the other hand,

the incidence also increased for intervals of 4

years or more since the previous Iive birth. These

variations were generally the same for white

births, but among black births the incidence decreased as the interval length increased up to 6

years and then rose for intervals of 6 years or

more.

The proportion of births occurring less than

2 years after a previous live birth was 1.4 times

as great among births to mothers who completed

less than 12 years of school as to mothers who

were at least high school graduates. The difference between these two educational groups in

the proportion of births occurring within 2 years

of the previous birth was smaller for higher birth

orders, declining from 1.6 for second births to

1.2 for fourth and higher births. This pattern

was the same for white and black births, but

there were somewhat smaller differences for

white births (table 14).

With few exceptions, the proportion of infants born less than 24 months after a previous

Iive birth was higher for black births than for

white births at all birth orders and educational

attainment levels in 1973. By 1975, this proportion was lower for bIack births than for white

births among mothers with 13 or more years of

school.

INTERVAL SINCE TERMINATION OF

LAST PREGNANCY AND OUTCOME OF

LAST PREGNANCY

The mother’s previous pregnancy experience

has been found to be a major factor associated

with the infant’s chance for survival.a! 17 In

1973, data on the outcome of the last pregnancy

of the mother were available for the 39 States

and the District of Columbia which reported the

dates of Iast live birth and fetal death. For all

births resulting from second and higher order

pregnancies, the mean interval since termination

of last pregnancy was 40.4 months. The length

of this interval was similar for white (40.6

months) and black (39.6 months) births.

The mean interval since termination of the

last pregnancy was approximately 1% years

longer when that pregnancy ended in a live birth

than when it ended in a fetal death. Table P

shows that this was generally true for all birth

orders. By age of mother, the interval since

termination of the last pregnancy was from 4

months to 3 years Ionger when the last pregnancy ended in a live birth than when it ended

in a fetal death. This difference increased with

age of mother. Although these patterns were the

same for births to mothers in both major racial

groups, the difference between the two pregnancy outcomes was slightly smzdler for black

births.

Between 1973 and 1975, there was an increase of 1 month in the interval since termination of the last pregnancy, from 40.4 to 41.4

months.

19
Table P. Mean interval since termination of last pregnancy by

outcome of last pregnancy, live-birth order, and age of

mother: total of 39 reporting States and the District of

Columbla, 1973

[See Technical Notes I

Live-birth order and

age of mother

All second and higher

order pregnancies ....................

Live-birth order

First births ...........................................

Second births .......................................

Third births ......................... .................

Fourth births .......................................

Fifth births and over ............................

Age of mother

Under 20 years ........................ .............

20-24 years ..........................................

25-29 years ....................................... ...

30-34 years ..........................................

35-39 years ....................... ...................

40 years and over .................................

Percent Low Birth Weight

tl- Last pregnancy

Tota I

Liva Fetal

birth death

lean interval in months

40.4 42.0

24.3

37.2 38:1”

44.1 45.2

46.8 47.9

46.4 47.4

21.1 21.6

30.4 31.4

40.4 41.9

53.7 55.8

68.8 71.4

81.2 83.9

24.2

24.3

21.7

25.5

27.9

28.6

17.7

20.6

24.0

29.9

38.7

47.7

The proportion of low-birth-weight infants

was about a third higher among births-to women

whose last pregnancy ended in a fetal death (9.3

percent) than among births to women whose last

pregnancy ended in a live birth (7.0 percent).

The figures below show that this was true for

both major racial groups.

White Black

Live birth ...................................... 6.0 12.9

Fetal death .................................... 8.1 17.2

Table 15 shows proportions of low-birthweight infants according to interval since termination of the last pregnancy. These data indicate that a longer interval is more favorabIe for

births following a previous live birth than for

births following a fetal death. Although the proportions of low-birth-weight infants were highest

for births occurring less than a year since a previous pregnancy regardless of the outcome of

that pregnancy, the proportion among those occurring subsequent to a live birth was over 11/2

times the proportion among those occurring subsequent to a fetal death.

It may be that the amount of time required

for the mother’s reproductive system to recover

from pregnancy and childbirth and for the body

to build up its reserves in preparation for another pregnancy is greater following a live birth

than a fetal death. In that case, births following

a previous live birth after a relatively short time

would probably be more likely to have an unfavorable outcome than births closely succeeding a fetal death.

Among births occurring subsequent to a previous live birth, the proportion of low-birthweight infants decreased as the interval increased

from 12-17 months to 36-47 months and increased for interyals of 4 years or more. In contrast, among births occurring subsequent to a

previous fetal death the level of low birth weight

increased as the interwd increased from 12-17

months to 5 years or more.

The range in the Ievel of low birth ‘weight according to intervals ~was greater arncmg births

following a live birth than following a fetal

death. When the pr&%us pregnancy endedjiw%

live birth, the proportion of low birth weight

among infants born less than a year since that

birth was 4 times as great as among infants born

at the most favorable interval, ~6-47 months

(20.4 compared with 5.1 percent). On the other

hand, for births occurring subsequent to a fetal

death the percent of low birth weight among

infants born within a year since the fetal death

was less than t%$ice the percent among those

born at the most favorable interval, 12-17

months (13.0 compared with 7.3 percent).

The relationships for white births were similar to those for total births, but for bla~ckbirths

there were some differences, The level of low

birth weight among black infants born less than

a year after a previous pregnancy was nearly the

same for infants born subsequent to a fetal

death (27.4 percent) as for those following a

live birth (29.5 percent). In addition, there were

slight differences in the pattern of low birth

weight occurring 4 years or more after both

a previous live birth and fetal death.

ILLEGITIMACY

In 1973, an estimated 407,300 illegitimate

births occurred in the United States, accounting

20
for approximately 13 percent of the 3,136,965

live births recorded in that year.

National estimates of the number of illegitimate births have been prepared annually since

1938. These estimates are based on information

entered on the birth certificates of the States

that require the reporting of legitimacy status.

In 1973, 38 States and the District of Columbia

required this information. For discussion of-the

procedure used in making natiomd estimates

of illegitimacy, see the “Technical Appendix” of

volume I of Vital Statistics of the United States.

Illegitimacy data have been tabulated by

race (white and black) since 1969. For years

prior to 1969, illegitimacy data were tabulated

by color only, necessitating use of the broader

category “all other” which consists of a.11races

other than white.

The estimated number of illegitimate births

has increased steadily each year since 1940, with

the exception of 1948. By 1975, the estimated

number had increased to 5 times the number in

1940 (table 16). During the two 10-year periods

1940-1950 and 1950-1960, there was a 58-permmitl increase; between -HMO and 1970 the increase was even greater, 78 percent. Since 1970,

the estimated number of illegitimate births has

increased at a slower pace, only 12 percent (to

1975); however, the majority of this increase

has occurred since 1973 (10 percent between

1973 and 1975). The number of illegitimate

births among the white population increased

between 1973 and 1975, following a decrease

between 1970 and 1972. Tke number of illegitimate births among all other races continued to increase during this period, but at a

slower pace than in previous years.

Two measures commonly used to describe

the incidence of illegitimacy are the illegitimacy rate and the illegitimacy ratio. The rate

is defined as the number of illegitimate births

per 1,000 unmarried women aged 15-44 years. It

is a measure of the probability that an unmarried woman wiIl bear a chiId. The illegitimacy ratio, defined as the number of illegitimate births per 1,000 total births, is a measure

of the proportion of total births that are classified as illegitimate.

The illegitimacy rate increased from 7.1

illegitimate births per 1,000 unmarried women

aged 15-44 years in 1940 to 26.4 in 1970 (tabIe

16). It decreased slightly since then to 24.1 in

1974; however, the rate increased to 24.8 in

1975. Although the illegitimacy rate for white

women followed the pattern just described, the

rate for all other women has decreased each year

since 1971.

Estimated illegitimacy rates by age of

mother and color for the period 1940-75 are

shown in figure 8 and by age of mother and race

for 1970-75 in table Q. Women in the prime

childbearing ages–20-24 and 25-29 years-had

the highest illegitimacy rates, followed by

women 15-19 years old; among women 30 years

and over the rate decreased with age. A similar

pattern was found for both racial groups.

In 1940, the rate for all other women was

nearly 10 times as great as the rate for white

women (35.6 and 3.6, respectively). During the

1940’s, the color differential increased until, by

1950, the rate for all other women was nearly

12 times as great as the rate for white women.

The differential decreased between 1950 and

1969, when it was more than 6, due both to the

more rapid increase in the rate for white women

during the 1950’s and to the decline in the rate

for all women after 1960. Between 1969 and

1971, the differential increased slightly to just

over 7; it remained relatively stable until 1975

when it declined to 6.4.

A leveling off or slight decIine in illegitimacy rates for white women occurred in the

mid- to late 1960’s for all but the 15-19-year age

group (see figure 8). Even greater decreases occurred between 1970 and 1974, especially for

age groups having the highest rates. However,

during 1975 rates increased for all white women

except for those aged 35 years and over. Rates

for a.11other women have Ieveled off or declined

slightly in the late 1950’s or early 1960’s for all

age groups and generally remained stable up to

the mid-1 960’s (except for the 30-34-year age

group in which the increase resumed). Beginning

in 1965, sharp declines occurred for all age

groups except ages 15-19 years oId.

The second commordy used measure of illegitimacy, the illegitimacy ratio, is a measure of

the proportion of births classified as illegitimate.

It is easier to compute than the illegitimacy rate

because the population data for unmarried

women needed to caIculate the rate are often

difficult to obtain. However, the ratio has num21
50C

400

300

m

l,ooil

900

800

700

600

. —.—-

*d+e-

------- .-~ .

““-7

\

..+ “

----

/“ ,. .“:.: s.

. ..”:-;”

,

100 ,t ----- , .--’

---- “.8<,’-----.”- -’%..*----

,

90 ,.- z - 4’ . -A II other, 20.24 yea \ -.

80 ,

. —

A II other, 15.19 yea,

70

AII other, 25.29 pat

60 ●.-

#.-

4’

.

so

,’

.-

/

.Z-.

4 .,’”

#

-.

AH other, 30.34 year.

40

,/ ,~’” # ...

.’

. . . . . .

. ...!.

. . . . . . . . . . .. . -.

30 ,’ . . .

. . . .

,.

. ...”

,’

..-

,’

0.-.

20

. ...”

. ..”

. . .

. . . Whine, 20.24 years

. ...”

. ...” tiWhtte, 25.29 years

. ..” t All other, 3544 yea=

. ...”

. ...”

10 ..“

Whne, 15.19 years

,...

9

/

/

Wh,m, 30.34 ve~n

a

7

5

./ . . . . . ...””” ““” ”.-. . . . . . .

4

..- . . .

. . . . . . . . . . . .

. ..”

. . . .

,/ . ..-

3 ... LJhite, 35.44 v~8rs

/“

,“ . ..””

. ...”

. ..”

. ...”

. ...”

2 . ..”

. . ...”

. . . .

. ...’

. . . . .

. . .

. . ...”

. ...””

. ...”

. ...”

I

1940 1950 1960 1965 1970 1975

YEAR

\

,,.....

\&,

‘% -..

--

‘.

+ /

-

,

...

$.

..%.

“%. . .

. . .

m

m

lrs

.

Figure 8. Estimated illegitimacy rates, by age of mother and color: United States, 1940-75

22
Table Q. Estimated illegitimacy rates by age of mother and race: United States, 1970-75

[See Technical Notes]

Race and age of mother

Al I racesl

All ages, 15-44 years2 ..................................................................................

15-19 yean ............................ .................................................... .............................

20-24 yearn ..... ................................................. ............. ..........................................

25-29 years .......... ...................................................... .............................................

30-34 years ..................................... ........................................................................

35-39 years .................................. ...........................................................................

40-44 years3 . ................................................ ............... ..........................................

White

All ages, 15-44 yearsz ..................................................................................

15-19 years .............................................................................................................

20-24 years .............................................................................................................

25.29 yea~ .............................................................................................................

30-34 years.............................................................................................................

35-39 years .............................................................................................................

40-44 yeaE3 ...........................................................................................................

Black

All ages, 15-44 years2 ..................................................................................

15-19 years .............................................................................................................

20-24 yean .............................................................................................................

25-29 years .............................................. .......................... .................. ...................

30-34 years ................................................. .................... ........................................

35-39 years .............................................................................................................

40-44 years3 ...........................................................................................................

lincludes races other than white and black

1975 1974 1973 1972 1971 1970

Rate per 1,000 unmarried women

24.8 I 24.1 ] 24.5

24.2 23.2

31.6 30.9

28.0 28.4

18.1 18.6

9.1 10.0

22.9

31.8

30.0

20.5

10.8

2.6 2.6 3.0

12.6 11.8 11.9

12.1 11.1

15.7 15.2

15.1 14.9

10.0 9.6

5.4 5.5

1.5 1.5

85.6 86.6

10.7

15.6

16.1

10.7

5.9

1.7

89.5

-1- 95.1 95.1

109.9 111.2

78.1 82.5

51.0 52.3

20.3 24.2

7.2 6.7

96.0

117.2

86.0

58.1

27.4

7.7

24.9

22.9

33.4

31.1

22.8

12.0

3.1

12.0

10.5

16.7

16.6

12.1

6.4

1.6

92.2

98.8

122.0

89.7

57.7

30.2

8.5

25.6

22.4

35.6

34.7

25.3

13.3

3.5

12.5

10.3

18.8

18.6

13.3

7.2

1.9

96.5

99.1

131.1

100.4

69.0

32.7

9.4

~Rates were computed by relating total illegitimate births regardless of age of mother to unmarried women aged 15-44 years.

‘Rates were computed by relating illegitimate births to mothers aged 40 years and over to unmarried women aged 40-44 years.

erous shortcomings when used as an anzdytic

tool. Th6 numerator and denominator of the illegitimacy ratio are affected by two independent

sets of factors. The numerator, the number of illegitimate births, is determined by the rate of illegitimacy and the number of unmarried women.

The denominator, the total number of births, is

influenced primarily by factors that affect the

level of maritaI fertility, such as changes in timing of births and compIeted family size. ObviousIy, if these factors change, the ratio will

change even if the numerator remains the same.

The illegitimacy ratio has increased substantially from 37.9 in 1940 to 142.5 in 1975

(table 16). Between 1970 and 1975 alone, there

has been a 33-percent increase in the ratio. The

increase has taken place in spite of a leveling off

26.4

22.4

38.4

37.0

27.1

13.6

3.5

13.9

10.9

22.5

21.1

14.2

7.6

2.0

95.5

96.9

131.5

100.9

71.8

32.9

10.4

or, in some cases, a decrease in the illegitimacy

rate since the mid-1960’s. A factor responsible

for the increase in the illegitimacy ratio during

this period is one that does not itself determine

the incidence of illegitimacy. This factor is the

decline in total, mainly marital, fertWy (affecting the denominator). Also responsible for the

increase in the illegitimacy ratio is the rising

numb er of unmarried women, a factor that affects the numerator.

There was a Iarge raciaI differential in the illegitimacy ratio in 1973 as in previous years: the

ratios for white and black births were 63.9 and

457.5, respectively. The racial differential has

increased since 1969, following a decline during

the early 1960’s.

Table R shows the estimated illegitimacy

23
Table R. Estimated Illegitimacy rat!os by age of mother and

race: United States, 1973

[ See Technical Notes]

Age of mother

Total ......................................

Under 15 years ....................... ...........

15-19 years .......................................

15 years .......................................

16 years .......................................

17 years .......................................

18 years ........ ...... .........................

19 years .......................................

20-24 years ........................ ...............

25-29 years ............. ..........................

30-34 years ........ ...............................

35-39 years .......................................

40 years and over ..............................

Ratio per 1,000 total

live births

1

129.8 63.9

847.5 652.1

339.2 190.9

661.8 442.6

508.4 312.2

387.2 221.0

293.1 166.9

224.0 122.8

108.2 53.4

48.5 23.6

50.0 24.3

64.7 33.0

76.9 41.1

457.5

964.3

709.8

914.6

849.2

769.8

648.5

560.7

386.3

257.0

233.4

229.0

231.8

lrnclude~ *aceS other than white and black.

ratios by age of mother for 1973. The highest

ratios were found among births to mothers

under age 20 and particularly under age 15,

when the proportion of married women and the

number of legitimate births are both small. The

ratio decreased with increasing age of mother up

to and including the age group 25-29 years even

though the illegitimacy rate shows these mothers

to be at greater risk of having an illegitimate

birth. The small ratio for births to mothers of

these ages is a reflection of the larger proportion

of married women and the high level of marital

fertility to these women who are in their prime

childbearing years. Thus, although the “risk” of

illegitimacy as measured by the illegitimacy rate

is high at ages 25-29, the proportion of births

that are illegitimate to women of those ages is

low. Age patterns by race are, for the most part,

similar to those for all women. However, ratios

for black women are nearly constant for those

aged 30 or older.

Education of Mother

About 1 out of 4 live births to women reporting less than 12 years of education was illegitimate (table S). This high proportion is

related to the fact that, for the United States as

a whole, about 40 percent of mothers in this

education group were under 20 years old, comTable S. Percent of live births illegitimate by educational attainment of mother and race: total of 33 reporting States and

the District of Columbia, 1973

[See Technical Notes ]

Years of school completed I

All

by mothar IIWhite Black

racesl

Total ......................................

lJ=l!JLK

O-8 years ........................................... 24.2 13.4 57.4

9-11 years ....................... .. ................ 27.2 13.7 59.9

12 years ............................................ 9.6 4.4 38.3

13-15 years ....................................... 5.7 2.6 28.9

16 years or more ............................... 1.1 0.7 7.7

I Includes ~ace5 other than white and black.

pared with 10 percent of those with 12 or more

years of education. As previously noted, there

are fewer married women in this age group and

thus fewer legitimate births. The proportion of

illegitimate births decreased as educational attainment increased, reaching a low of 1.1 percent for mothers reporting 16 or more years of

school.

The proportion of illegitimate births was

higher among black than among white women

for all levels of education. However, the racial

differential increased as education increased,

ranging from 4.3 times as great for black women

at the lowest level of educational attainment

(57.4 percent versus 13.4 percent) to 11.0 times

as great at the highest level (7.7 percent versus

0.7 percent).

Percent Low Birth Weight

Illegitimate births are more likely to be of

low birth weight than are legitimate births (table

T). In 1973, as in previous years, nearly twice as

great a proportion of illegitimate (12.8 percent)

as legitimate births (6.8 percent) weighed 2,500

grams or less at birth. Although the proportion

of low birth weight is greater for illegitimate

than for legitimate births for both major race

groups, the difference among black births is less

than one-half that among white births (24 percent versus 60 percent). However, among births

to younger mothers (white mothers 15 years

or younger and black mothers 16 years or

younger), there was a slightly higher proportion

of low birth weight among legitimate births.

The difference in percent low birth weight

by legitimacy status cannot be attributed solely

24
Table T. Percent of live births of 2,500 grams or less by legitimacy status, age of mother, and race: total of 38 reporting States and the

District of Columbia, 1973

[See Technical Notes]

All racesl White Black

lllegitimate

Age of mother

LegitimateLegitimateillegitimate

Legitimate

lllegitimate

Total ................................................................................................ 6.8 12.8 6.2 9.9 11.9 14.8

14.0

8.5

10.9

9.9

9.0

8.5

7.7

6.6

6.0

6.6

8.0

9,0

9.2

16.0

12.7

13.1

12.7

12.7

12.6

12.4

12.6

12.7

13.2

15.7

15.6

16.1

12.6

7.7

10.0

9.1

8.3

7.6

6.9

5.9

5.5

6.1

7.2

8.2

9.0

12.2

9.4

9.3

9.3

9.1

9.7

9.6

9.7

10.4

11.6

14.2

18.6

9.3

20.2

14.0

17.0

15.8

14.9

14.1

12.9

11.6

11.1

10.9

12.3

13.1

10.3

17.6

14.8

15.2

14.9

15.0

14.6

14.3

14.6

14.5

14.4

16.9

13.6

23.3

Under 15 years .................................................. ..............................................

15-19 years ..................................................................... .................................

15 years ......................................................................................................

16 years ........... ................................. ..........................................................

17 years ......................................................................................................

18 years ..................................................... .................................................

19 years ................................................................. .....................................

20-24 years ..................... ........................................................................... ......

25-29 years ......................................................................... .............................

30-34 years ...................................... ................................................................

35-39 years ........................ .................... ..........................................................

40-44 years ..................................................................... .................................

4549 years .................. ....................................................................................

llncl~des races other than white and black.

to the difference in socioeconomic status between these two groups. The percent low birth

weight was higher among illegitimate than among

legitimate births for all educational levek for

both racial groups (table U). The differential was

greater for white than for black births, ranging

from 27 to 109 percent among white births and

from 18 to 46 percent among black births. The

differential increased with increasing levels of

education among mothers who had more than 8

years of schooling.

Prenatal Care

Mothers of legitimate births are more likely

to seek prenatal care and to seek it at an earlier

stage of pregnancy than are mothers of illegitimate births (tabIe V). The vast majority of

legitimate births (75 percent) were to mothers

who began prenataI care by the third month of

pregnancy, while less than half (39.5 percent)

of the illegitimate births were to mothers who

began care during the first trimester of pregnancy. Only 1.0 percent of legitimate births

were to mothers who had no prenatal care, as

opposed to 5.2 percent of illegitimate births.

The same variations are observed when the data

are examined by race, but the differences are

smaller among black births.

Table U. Percent of Iiva births of 2,500 grams or less by educational attainment of mother, legitimacy status, and

race: total of 33 reportirm States and the District of

Columbia, 1973 -

[See Technical Notesl

Race and years of school com1 II Total Legitpleted by mother imate

legitimate

All racesl ..............................

T

7.6 6.8

10.6 9.4

10.1 8.9

6.8 6.3

5.9 5.6

6.0 5.0

12.9

14.4

13.5

11.7

10.9

11.2

9.9

0-8 years ................................... .......

9-11 years ........................................

12 years ..... .............. ........................

13-15 years .......... ............................

16 years or more ..............................

;1

6.4 6.1

9.1 8.7

8.4 8.1

5.8 5.7

5.1 5.1

4.6 4.6

13.2 11.8

15.2 13.7

14.5 13.1

12.2 11.3

11.1 10.4

9.5 9.1

White .....................................

11.9

10.3

8.8

8.1

9.6

14.9

16.3

15.5

13.6

12.8

13.3

0-8 years ................................... .......

9-11 years ............ ...... ......................

12 years ............... ............................

13-15 yaars ............ ..........................

16 vears or more ... ............ ........ ...... .

Black ................. ....................

O-8 years ............ ........ ......................

9-11 Vears ... .....................................

12 years .... .......................... ...... .......

13-15 years ........... ............ ...............

16 years or more ..............................

1 Includes races other than white andblack.

25
Table V. Percent distribution of live births by month of pregnancy’ prenatal care began, by legitimacy status and race: total of 33

reporting States and the District of Columbia, 1973

[See Technical Notes]

Race and month of pregnancy

prenatal care began

Legitimate

100.0

46.5

28.5

20.2

3.8

1.0

100.0

48.2

28.9

18.7

3.4

0.8

100.0

33.8

25.4

31.8

6.7

2.4

-—

legitimate

100.0

19.3

20.2

41.6

13.7

5,2

100.0

19.0

19.7

39.7

16.4

5.2

100.0

19.6

20.7

43.1

11.6

5.0

000
REFERENCES

lNationd Institutes of Health: HOW children gSOW.

Clinical Resi?arch Advances in Human Growth and Deuelopnzent. DHEW Pub. No. (NIH) 72-166. Public Health

Service. Washington. U.S. Government Printing Office,

June 1972. p.15.

2Penchaszadeh, V. B., Hardy, J. B., Mellits, E.D., et

al.: Growth and development in an “inner city“ population: An assessment of possible biological and environmental influences, II. The effect of certain maternal

characteristics on birth weight, gestational age and

intra-uterine growth. Johns Hopkins Med. ]. 131:11-23,

July 1972.

3Niswander, K. R., Singer, J., Westphal, M., and

Weiss, W.: Weight gain during pregnancy and prepregnancy weight. Association with birth weight of term

gestation. Obstet. Gynecol. 33(4) :482-491, Apr. 1969.

4National Center for Health Statistics: A study of infant mortality from linked records by birth weight,

period of gestation, and other variables, United States,

1960 Iive-birth cohort. Vital and Health Statistics. Series

20, No. 12. DHEW Pub. No. (HSM) 72-1055. Washington. U.S. Government Printing Office, May 1972.

5National Center for He~th statistics: Selected vital

and heaIth statistics in poverty and nonpoverty areas of

19 Iarge cities, United States, 1969-71. Vital and Heatth

Stat&tics. Series 21, No. 26. DHEW Pub. No. (HRA)

76-1904. Health Resources Administration. Washington.

U.S. Government Printing Office, Nov. 1975.

6Bergner, L., and Susser, M.: Low birth weight and

prenatal nutrition: An interpretative review. Pediatrics

46(6) :946-966, Dec. 1970.

7Westphal, M. C., and Joshi, G. B.: The interrelationship of birth weight, length of gestation, and neonatal

mortality. Clin. Obstet. Gynecol. 7:670-686, Sept. 1964.

8Kane, S. H.: Significance of prenatal care. Obstet.

Gynecol. 24(1):66-72, July 1964.

9Terris, M., and Glasser, M.: A life table analysis of

the relation of prenatal care to prematurity. Am. j. Public Health 64(9) :869-875, Sept. 1974.

10Terris, M., and Gold, E.: An epidemiologic study

of prematurity. Am.. J. Obstet. GynecoL 103(3) :371-

379, Feb. 1969.

11Markle, G- E.: Sex ratio at bfith: v~ues, Vmiance,

and some determinants. Demo~aphy 11(1):131-142,

Feb. 1974.

12Twer, J. D., ~d Lee, C.: Sex ratio of registered

live births in the United States, 1942-63. Demography

5(1):374-381, Feb. 1968.

13Myers, R. J.: The effect of age of mother and birth

order on sex ratio at” birth. Milbank Mere. Fund Q.

32(3) :275 -281, July 1954.

14Tietze, C.: Legal abortions in the United States:

rates and ratios by race and age, 1972-74. Fare. Plann.

Perspect. 9(1):12 -15, Jan./Feb. 1977.

15National Center for Health Statistics: Contraceptive

utilization among currently married women 15-44 years

of age: United States, 1973. Monthly Vital Statistics RePort. Vol. 25, No. 7, &lppl. DHEW Pub. No. (HRA) 76-

1120, Public Health Service. Washington. U.S. GovernmentPrinting Office, Oct. 4, 1976.

16Reportof a WHO Scientific Group. Health aspects

of family planning. WHO Tech. Rep. Ser. No. 442, 1970.

17National Institutes of Health: The women and their

pregnancies. Collaborative Perinatal Study of the National Institute of Neurological Diseases and Stroke.

DHEW Pub. No. (NIH) 73-379, Public Health Service.

Washington, U.S. Government Printing Office, 1972.

p. 185.

27
LIST OF DETAILED TABLES

1. Percent of births to mothers completing 12 or more years of school by live-birth order, aga of mother, and race: total of 41

reporting States and the District of Columbia, 1973 ............................................................................................. ....................

2. Percent distribution of live births by educational attainment of father, age of father, and race: total of 41 reporting States

and the District of Columbia, 1973 ........ .................................................. .................................................................................

3. Percent distribution of live births by educational attainment of mother, age of mother, and race: total of 41 reporting States

and the District of Columbia, 1973 ...........................................................................................................................................

4. Median birth weight and percent of live births of 2,500 grams or lees, by race and sex: United States, 1960, 1965, 1970,

1973, and 1975 .........................................................................................................................................................................

5. Percent of live births of 2,500 grams or less, by place of residence and race for metropolitan and nonmetropolitan counties:

United States, 1960, 1965, 1970, 1973, and 1975 ....................................................................................................................

6. Percent of live births of 2,500 grams or less, by age of mother, educational attainment of mother, and race: total of 41

reporting States and the District of Columbia, 1973 .................................................................................................................

7. Median number of pranatal visits and percent distribution of births by month of pregnancy prenatal care began, by age

of mother and race: total of 42 reporting States and the District of Columbia, 1973 ................................................... ...........

8. Median number of prenatal visits and percent distribution of births by month of pregnancy prenatal care began, by livebirth order and race: total of 42 reporting States and the District of Columbia, 1973 ............................. .................................

9. Percent distribution of live births by month of pregnancy prenatal care began, educational attainment of mother, and

rata: total of 38 reporting States and the District of Columbia, 1973 .......................................................................................

10. Percent distribution of live births by attendant and place of delivery, race, and place of residence: United States, 1960,

1970, 1973, and 1975 ...............................................................................................................................................................

11. Parcent distribution of live births by attandant and place of delivery and race: United States and each geographic division,

1973 .........................................................................................................................................................................................

12. Mean intarval since last live birth by live-birth order, educational attainment of mother, and race: total of 38 reporting

States and the District of Columbia, 1973 ................................................................................................................................

13. Percent of live births of 2,500 grams or less, by age of mother, interval since last live birth, and rata: total of 40 reporting

States and the District of Columbia, 1973 ................................................................................................................................

14. Percent of births occurring less than 24 months since the previous live birth by live-birth order, educational attainment of

mother, and race: total of 38 reporting States and the District of Columbia, 1973 ...................................................................

15. Percent of live births of 2,500 grams or less by outcome of last pregnancy, interval since termination of last pregnancy, and

race: total of 39 reporting States and the District of Columbia, 1973 .......................................................................................

16. Estimated number of illegitimate live births and illegitimacy ratios and rates, by race: Unitad States, 1940, 1950, 1960,

and 1965-75 ... ...........................................................................................................................................................................

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

28
Table 1. Percent of births to mothers completing 12 or more years of school by live-birth order, age of mother, and race: total of 41

reporting States and the District of Columbia, 1973

[See Technical Notes]

Age of mother and race

Live-birth order

8th

and

war

35.5

1St 4th

Total

2d 3d 5th 6th 7th

All racesl ..................................................................... 69.4

=

36.0

75.5

82.8

77.4

67.0

58.9

73.3

70.7

-

39.9

88.3

93.6

89.9

81.9

75.9

74.4

76.1

23.5

74.0

90.5

88.8

80.6

72.4

78.7

69.1

=

13.0

50.4

78.5

83.3

76.9

69.9

72.2

61.3 54.0 48.0 43.7

15-19 years ...................................................................................

20-24 yaars...................................................................................

25-29 years...................................................................................

30-34 years...................................................................................

35-39 years...................................................................................

40 years and over .........................................................................

9.9

30.7

61.8

75.2

72.4

68.5

64.9

*

21.3

45.3

63.9

66.4

64.1

58.3

*

13.9

25.4

42.8

53.4

56.2

50.6

*

32.9

16,3

29.8

39.2

42.8

15.5

31.0

52.4

61.2

59.3

White ................................................................................. 53.6 46.3

15-19 years ...................................................................................

20-24 years...................................................................................

25-29 years...................................................................................

30-34 years...................................................................................

35-39 yeaw ...................................................................................

40 years and over .........................................................................

38.3

77.8

85.0

80.5

71.0

64.7

51.5

42.4

89.0

94.1

90.6

83.3

77.5

52.1

33.1

84.8

87.8

83.0

69.7

67.5

21.5

75.1

91.2

89.6

81.1

74.1

60.5

8.3

51.5

79.7

84.4

77.8

72.2

54.0

8.4

30.5

63.6

76.9

73.8

70.2

46.8

10.8

31.0

54.6

62.6

62.9

56.1

*

12.2

30.2

48.8

58.1

60.8

29.8

*

44.9

24.6

38.9

49.3

53.4

19.6

47.6

66.8

66.4

65.8

40.5

13.0

33.6

56.8

64.7

63.0

Black ................................................................................. 34.0 20.7

*

19.8

10.6

20.1

23.8

21.6

15-19 years............................................................b......................

20-24 years...................................................................................

25-29 years...................................................................................

30-34 years...................................................................................

35-39 years...................................................................................

40 years and over .........................................................................

30.9

65.3

66.2

57.9

48.0

36.5

27.1

69.0

82.6

80.8

74.5

61.5

17.1

47.8

69.7

73.1

69.3

54.9

*

23.1

39.6

50.5

55.2

53.1

*

14.5

20.7

30.8

40.5

37.3

16.9

27.3

39.6

45.9

43.4

lIn~l~des races other than white and black.

29
Table 2. Percent distribution of live births by educational attainment of father, age of father, and race: total of 41 reporting States and

the District of Columbia, 1973

[See Technical Notes ]

Years of school completed by father

Age of father and race

All racesl ........................................... ..............................................

White ............................................................................................. ........

Black .......... ...........................................................................................

Total

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

0-6

7.4

=

6.4

5.4

5.3

7.4

13.2

20.0

26.4

34.0

49.4

7.1

6.8

5.5

5.2

7.1

12.5

18.5

24.4

31.4

43.7

9.3

4.0

4.5

7.0

11.2

18.4

28.9

35.1

43.0

57.9

9-11

16.6

45.0

20.0

11.8

12.2

14.6

15.3

17.8

15.2

14.0

15.3

44.5

19.0

10.7

11.0

13.0

13.9

16.5

13.8

14.2

26.5

47.4

25.9

22.7

24.1

27.4

24.6

24.6

21.1

16.2

Total

75.9

48.7

74.7

82.8

80.4

72.2

64.8

55.8

60.8

36.6

77.5

48.6

75.6

84.1

81.9

74.5

67.6

59.1

54.8

42.1

64.1

48.6

69.7

70.3

64.7

54.3

46.5

40.1

35.9

25.9

12 or more

12

42.2

43.9

50.1

40.6

37.6

36.9

34.3

30.0

28.3

20.9

41.8

44.0

49.6

40.0

37.4

37.4

34.9

30.7

29.3

23.8

46.1

43.4

52.8

47.5

42.1

36.3

31.2

27.7

25.3

15.3

13-15

15.9

4.7

17.6

18.7

15.2

12.5

10.9

9.7

9.1

6.3

16.5

.—

4.5

18.2

19.1

15.6

13,0

11.3

10.5

10.0

6.9

12.0

5.1

13.8

14.3

12.1

9.5

8.4

6.2

5.5

5.8

——

160r

nora

17.8

0.1

7.0

23.5

27.6

22.8

19.6

16.1

13.4

9.4

19.2

0.1

7.7

25.0

28.9

24.1

21.4

17.9

15.5

11.4

6.0

0.1

3.1

8.5

10.5

8.5

6.9

6.2

5,1

4.8

1lncludes ~ace~ Other than white and black.

30
Table 3. Percent distribution of live births by educational attainment of mother, age of mother, and race: total of 41 reporting States

and the District of Columbia, 1973

[See Technical Notes]

Age of mother and race

All racesl .................................... .............. ........................ ...............

15-19 years .................................................................................................. .. ...

20-24 yean .................. .............................. ............ ...........................................

25-29 years .............l .......... ........ ............ .......................... .................................

30-34 years .................................................................................... ...................

35-39 years ...... .......... .................. .................................... ...... ...........................

40 years and over ........................ .............. ............ .............. .............................

White .............................................................. ........................ .. .............

15-19 years .................................................................... ...................................

20-24 years .................................. .......................................................... ...........

25-29 years ........................................ .................................................... ...........

30-34 years .............................................................................. .........................

35-39 years ................................ ...... ............ ...................................... ...............

40 years and over ...... .......................... ........ .................... ...... ............ ........ .......

Black ........... ..........................................................................................

15-19 years ........................ ...............................................................................

20-24 years .................................................. .....................................................

25-29 years .. ..................................................... ..... ............... ..................... .......

30-34 years ..................................................................................................... ..

35-39 years ...................................................... ............................................. ....

40 years and over ...................... ........................................................... ....... .....

II Years of school completed by mother

Total

o-B

100.0 6.7

100.0 8.5

100.0 4.8

100.0 4.8

100.0 7.5

100.0 13.9

100.0 20.6

100.0 6.0

100.0 8.7

100.0 4.6

100.0 4.3

100.0 6.6

100.0 12.6

100.0 17.9

100.0 9.1

100.0 8.2

100.0 5.4

100.0 7.6

100.0 12.3

100.0 18.6

100.0 29.0

—

9-11

24.0

55.4

19.7

12.4

15.0

19.1

20.6

20.7

53.1

17.7

10.7

12.9

16.4

17.4

39.4

61.0

29.2

26.2

29.8

33.4

34.5

Total

69.4

36.0

75.5

82.8

77.4

67.0

58.9

73.3

38.3

77.8

85.0

80.5

71.0

64.7

51.5

30.9

65.3

66.2

57.9

48.0

36.5

12 or more

12

45.4

33.3

54.2

45.1

42.7

42.6

39.6

47.1

35.7

55.5

45.5

43.8

44.8

43.2

38.9

27.9

49.0

45.0

39.3

34.3

26.3

13-15

14.0

2.6

16.6

18.8

15.1

11.9

10.0

15.1

2.5

17.3

19.6

15.9

12.9

11.1

9.1

2.9

13.5

12.8

10.2

7.5

5.6

6 or

nore

10.0

0.1

4.7

18.9

19.6

12.5

9.3

11.1

0.1

5.0

19.9

20.8

13.3

10.3

3.5

0.0

2.8

B.4

8.4

6.3

4.5

lln=ludes races Other thsn white and black.

31
Table 4. Median birth weight and percent of live births of 2,500 grams or less, by race and sex: United States, 1960, 1965, 1970,1973,

and 1975

[See Technical Notes]

Rata and sex I

1975

I

1973

I

1970

I

1965

I

1960 1975 1973 1970

i

I

Median weight in gramsl I

Percent weighing 2,500 grams or less

All races .............................. ...............

L

3,320

Male ................................................................... 3,390

Female ............................................................ ... 3,260

White .. .............................. ....................... j 3,360

Male ..................................................... ...... ........

I

3,430

Female .............................................................. . 3,300

Ail other ....................................... ............

1-

3,160

Male ................ ................ ...... ............................. 3,210

Female ............................................................... 3,100

Black .............................................

L3,140

Male ..... ............................ .. ................................

I

3,200

Female ............................................................... 3,080

m

3,350 I 3,330 I 3,320 I 3,340 j 6.3

3,420 3,390 3,380 II3,400 5.8

3,290 3,270 3,260 3,280 6.8

3,150 3,140 3,130 3,150 12.2

I I I 1

3,210 11.2

13.4

3,140 3,120 --- --- 13.1

3,190 3,180 --- --- 11.9

3,080 3,070 --- --- 14.4

7.6 7.9 8.3 7.7

6.9 7.3 7.6 7.1

8.3 8.6 9.0 8,4

6.4 6.8 7.2 6.8

5.9 6.3 6.6 6.3

7.0 7.4 7.8 7.4

12.5 13.3 13.8 12.8

11.4 12.2 12.4 11.6

+++

13.7 14.4 15.1 14.1

13.3 13.9 --- ---

12.0 12.7 --- ---

14.5. 15.1 --- ---

lcomputed to nearest I o grams on exact conversion of interval from pounds and ounces.

32
Table 5. Percent of live births of 2,500 grams or less by place of residence and race for metropolitan and nonmatropolitan counties: United States, 1960, 1965, 1970, 1973, and 1975

[See Technical Notes ]

Type of county and year

Race and place of residence

All other

All races White

Total Black

All

areas

Balance

of

area

3almce

of

wea

Bal- BalAll

areas

Urban

placesl

All

weas

Urban

placesl

6.4

6.6

7.0

7.4

7.1

6.4

6.6

7.0

7.5

7.1

6.5

6.5

6.9

7.4

7.0

Urban

placesl

All

areas

Urban

placesl

ante ante

of

area

of

area

United States

1975 ...................... ..............

1973 ............................ ........

1970 ...... ........ ......................

1965 ....................................

1960 .......................... ..........

7.4

7.6

7.9

8.3

7.7

7.6

7.7

8.1

8.5

8.0

7.1

7.3

7.6

7.8

7.3

8.0

8.1

8.5

8.9

8.3

8.1

8.2

8.6

9.1

8.4

7.5

7.6

7.9

8.3

7.7

6.7

6.9

7.2

7.5

7.0

6.4

6.4

6.9

7.3

6.8

6.9

7.2

7.5

7.7

7.2

6.3

6.4

6.8

7.2

6.8

6.3

6.4

6.9

7.3

6.9

6.3

6.5

6.8

7.0

6.7

6.1

6.3

6.6

6.9

6.5

5.9

6.0

6.5

6.8

6.4

6.2

6.5

6.8

6.9

6.6

12.2

12.5

13.3

13.8

12.8

12.5

12.7

13.6

14.5

13.7

11.6

11.9

12.4

12.2

11.1

12.6

13.0

13.7

14.6

13.9

12.7

13.0

13.8

14.8

14.0

12.5

12.7

13.4

13.4

13.1

11.2

11.5

12.0

12.1

11.0

11.0

10.9

12.0

12.9

12.1

11.3

11.7

12.1

11.8

10.6

13.1

13.3

13.9

---

.-.

13.2

13.4

14.1

..-

..-

12.7

12.8

13.1

. . .

. . .

13.4

13.6

14.2

-..

. . .

13.4

13.6

14.3

-..

.-.

13.2

13.2

13.9

---

---

12.3

12.4

12.8

.-.

. . .

12.1

11.9

12.8

..-

. . .

12.4

12.6

12.8

-..

. . .

Metropolitan counti%

1975 ............ .......... ..............

1973 ....................................

1970 ....................................

1965., ...... ........................ ....

1960 ....................................

Nonmetropolitan counties

1975 ....................................

1973 ....................................

1970 ....................................

1965 ....................................

1960 ....................................

lplaces with 10,cscKIresidentso rmorein1960f orthe yea~1960 and196S andl O,OOOresidents OrmOrein l97Ofor197O-75.

33
Table6. Percent of live births of 2,500 grams or less, by age of mother, educational attainment of mother, and race: total of 41

reporting States and the District of Columbia, 1973

[See Technical Notes]

Age of mother and race Total

O-8

7.7 10.4

10.1 11.7

7.3 9.7

6.4 8.9

7.0 9.2

8.5 10.5

9.2 10.6

10.1 9.9

6.5 9.0

8.1 10.2

6.1 8.8

5.7 7.7

6.3 8.4

7.6 9.3

8.5 9.8

9.2 8.3

13.3 15.0

14.8 15.7

12.9 14.1

11.9 14.3

12.0 13.1

12.8 13.7

12.3 12.3

13.7 14.3

Years of school completed by mother

13-15

16

or

more

Less

than

12

12

12

or

nore

9-11

All racesl .............................................................................. 10.3 6.9 5.9 5.1 10.3 6.4

10.9

9.8

9.5

9.9

10.8

10.7

13.0

8.6

8.4

6.7

6.3

6.7

7.8

8.6

6.7

5.9

8.6

5.8

5.5

6.3

6.9

7.2

13.2

5.2

11.4

5.2

4.8

5.3

6.3

7.2

10.1

4.7

11.0

9.8

9.3

9.6

10.6

10.7

11.4

8.7

8.4

6.4

5.8

6.3

7.3

8.2

8.4

White. ........................ ............. ................................................... 5.6

8.7

8.3

8.2

8.6

9,8

10.0

14.4

14.7

6.7

5.7

5.7

6.1

7.0

8.4

5.4

12.2

7.1

4.9

5.1

5.8

6.4

6.1

12.6

11.0

10.0

4.6

4.5

5.0

5,5

6.7

10.5

9.5

8.9

8.4

8.1

8.5

9.6

9.9

11.3

14.8

6.7

5.4

5.3

5.7

6.6

7.7

7.5

Black ............................................ ........ ...................... ........ ........ 11.8

15.4

14.5

13.6

13.7

13.3

12.7

10.5

13.3

12.2

11.5

11.1

12.1

10.9

15.4

11.6

11.2

10.2

11.1

10.7

16.0

17.6

11.5

9.7

9.0

9.4

71.3

12.3

15.4

14.5

13.7

13.5

13.4

12.5

12.4

13.2

1149

11.0

10.9

11.8

11.8

15.5

lIncludes races Other than white and black.

34
Table7. Madian number of prenatal visits and percent distribution of births by month of pregnancy prenatal care bagan, by age of

mother, and race: total of42reporting States andthe District of Columbia, l973

[See Technical Notes ]

Age of mother and race

Month of pregnancy

prenatal care began Median

number

of

visitsl

No

pre-

)atal

care

Total

1st2d

43.8

4th6th7th9th 3d

All races2 .................................. ................. ........................ ............. 10.6 I00.0 27.0 22.6 5.2 1.5

Under 15 years ................................ .......................................................... ......

15-19 years ........ .............. .. ................................ .................................... ..........

20-24 years ......................................................................................................

25-29 years ................................................................................... ...................

30-34 years ....................................................................... ...............................

35-39 years ................................................................................ ...... ................

40-44 years ....... ...............................................................................................

4549 years ............ .................................................................................... ......

7.3

9.2

10.7

11.2

10.9

10.3

9.8

9.1

10.9

100.0

100.0

I00.0

I00.0

I 00.0

100.0

100.0

I 00.0

100.0

14.0

27.3

45.0

52.5

48.8

41.4

33.9

25.4

47.1

14.7

30.2

48.1

54.7

51.0

43.8

36.1

26.8

28.2

16.9

25.2

27.5

27.4

27.8

27.4

26.4

26.1

27.8

46.6

36.0

21.3

16.0

18.5

23.7

29.4

36.3

19.7

16.8

9.0

4.8

3.2

3.8

5.6

7.4

9.5

4.3

5.7

2.5

1.4

0.9

1.1

1.8

2.8

2.7

White .............................................................. ...................................... 1.1

5.4

1.9

1.0

0.6

0.8

1.5

2.2

1.9

3.4

Under 15 years ...... ............................................... ...................................... .....

15-19 years ................................. ............ ...... .................................. .... .. ...........

20-24 years .......................................................... .................................... ........

25-29 years ........................................................................... .................. .........

30-34 years .................................................................................................... ..

35-39 years ......................................... .................................................. ...........

4044 years ........................... ...........................................................................

4549 years ............................................. ........................ ...... .......................... .

8.0

9.8

11.0

11.4

11.1

10.6

10.1

9.5

8.6

I 00.0

100.0

100.0

I 00.0

I00.0

100.0

I 00.0

100.0

100.0

18.1

26.8

28.2

27.7

28.3

27.9

27.0

27.9

23.2

45.3

33.2

18.7

14.2

16.6

21.8

27.9

34.7

36.1

16.5

8.0

4.0

2.7

3.2

5.0

6.7

8.6

Black ........... .............. .............. ...... .............................................. ......... 9.0

Under 15 years .......... ...................................................... ................................

15-19 years ........................ .................... .................... ...... .......................... ......

20-24 years ............................................................................................. .........

25-29 years ........................... ...... ................ .... .. .................. ...... .......................

30-34 years ..................................................... .................................................

35-39 years ............... .............. ...... ...... ............................ .. ...... ............ ........ .....

40-44 years .................................................. ....................................................

4549 years .................... ........................................ .................... ......................

6.9

7.7

8.8

9.6

9.4

8.9

8.6

8.1

100.0

100.0

I 00.0

100.0

100.0

I 00.0

I 00.0

!00.0

13.4

20.4

30.2

36.5

35.1

29.8

24.8

21.3

16.2

21.4

24.1

24.7

24.3

24.6

24.1

20.0

47.6

43.3

34.0

29.4

30.8

33.7

35.6

41.6

16.8

11.0

8.5

6.8

7.0

8.5

10.2

12.8

5.9

3.9

3.2

2.6

2.8

3.3

5.4

4.4

lJjasedoninfor~ation from 38report@St atesandtheDi strict Of ColUITlbla.Excludes births tomc.ther swithrmvisits.

21nclUdes racesother than white aid black.

35
Table8. Median number of prenatal visits and percent distribution of births by month of pregnancy prenatal care bagan, by live-birth

order and race: total of 42reporting States and the District of Columbia, 1973

[See Technical Notes ]

Live-birth order and race

All races2 ........................................................................................

White. .................................... ................................................ .......... .....

Black .......................... ..........................................................................

Median

number

of

visital

10.6

10.7

10.8

10.5

10.1

9.6

8.7

10.9

11.0

11.1

10.8

10.4

10.0

9.2

8.6

8.7

8.7

8.7

8.4

8.3

7.6

Total

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

Month of pregnancy

prenata I care bagan

mFE

T

43.8 27.0 22.6

44.3 26.8 22.9

48.2 27.8 18.9

44.2 27.8 21.7

38.7 27.3 25.7

34.2 26.7 28.9

26.6 23.6 34.2

47.1 I 27.8 I 19,7

47.5

51.2

47.2

41.4

36.5

28.6

28.2

27.3

28.5

28.6

28.4

27.9

24.7

23.2

28.1 23.9

30.6 23.4

29.4 23.9

27.9 23.1

26.6 22.9

22.4 21.3

20,2

16.4

19.2

23.3

26,5

32.2

36.1

5.2 I 1.5

4.8 1.2

4.0 1.2

4.7 1.5

6.1 2.1

7.6 2.7

11.1 4.5

4.3 ] 1.1

4.1

3.2

3.8

5.3

6.8

10.6

9,0

0.9

0.8

1.1

1.6

2.3

3.9

3.4

37.2 8.2 2.6

34.0 8.6 3.5

34.2 8.7 3.8

35.8 9.1 4.2

37.0 9.6 3.9

39.1 11.5 5.6

lBa~ed on information from sgrep~rting States and the District of Columbia. Excludes birthe. to mothers with no visits.

‘Includes races other than white and black.

36
Table9. Percent distribution of live births by month of pregnancy prenatal care began, educational attainment of mother, and

race: total of38reporting States andthe District of Columbia, 1973

[See Technical Notes ]

Years of school completed by mother and race

All races 1................................................................................................... .......

O-8 years ......................................................................................................... ..................

9-11 years ...................... .............. ........ ............ .................... ...... .......................................

12 years ................................................... ........ ......................... ........................................

13-15 years ................ .................................................. .....................................................

16 years or more ............................................................... .................... ............................

Less than 12 yaars ................................ ......................................... ...................................

12 years or more ............................... ................................................ .............................. ..

White .....................................................................................................................

O-8 years ....................................... ....................................................................................

9-11 years ................................... ........................... .................... .................. .....................

12 years ................................................................ ........ ........................ ............................

13-15 years .................................................. ................................... ..................................

16 years or more ............. ............................................................................................ ......

Less than 12 years ................................................. .............................................. .............

12 years or more ............................................................................................... ................

Black ................................................................................................................. .....

Less than 12 years .............. .......................... .................................. ..................................

12 years or more ................................... .................................. .....................................<....

Total

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

1st2d

43.3

26.4

30.2

46.3

53.7

60.0

29.4

49.7

47.0

28.5

33.9

49.3

55.9

61.1

32.7

52.4

27.2

19.8

21.4

30.2

39.2

52.4

21.1

33.3

Month of pregnancy

prenatal care began

D

3d 4th- 7th6th 9th

27.2 23.0 5.2

23.1 35.1 11.7

25.1 33.6 8.8

28.6 20.5 3.8

27.8 15.3 2.8

26.9 11.3 1.7

24.7 33.9 9.4

28.2 18.2 3.3

28.2 19.8 4.1

24.4 33.0 11.0

26.8 30.2 7.6

29.4 17.8 3.0

28.1 13.5 2.2

27.0 10.4 1.4

26.3 30.8 8.3

28.8 15.8 2.6

22.7 37.1 9.6

J-L 19.5 42.1 13.4

21.2 41.8 11.4

24.2 34.8 8.1

25.0 27.6 6.5

25.0 18.2 3.7

20.8 41.9 11.8

24.4 32.4 7.6

No

welatal

care

1.3

3.7

2.3

0.8

0.4

0.2

2.6

0!7

0.8

3.0

1.5

0.5

0.3

0.1

1.8

0.4

3.4

5.3

4.2

2.7

1.6

0.7

4.4

2.3

11nclude5 races other than white and black.

37
Table 10. Percent dlstr)but,on ofliveb,rths byattendant andplace ofdellvery, race, andplace 0fresidence: United States, 1960, 1970, 1973, and 1975

[See Technical Notes 1

I

Year and place of residence

Race and attendant and place of delivery

r

United

States

1975

Urban

placesl

Bal.

1973

Urban

placesl

f3alance

of

cxxmtry

1970

Balance

of

cOuntrvnT1980

BalUnited Urban ante

States placesl &f”.

try

ante )nlted

States

United

States

Urban of

cOunw

placesl

T

100.0 100.0 100.0

99.6 99.0 96.6

0.1 0.2 1.2

0.2 0.7 2.0

0.1 0.1 0.2

100.0 100.0 100.0

99.7 99.7 9B.8

0.1 0.1 0.7

0.1 0,1 0.4

0.1 0.1 0.1

100.0 100.0 100.0

1

All races.................................................. ......

1

100.0

98.7

0,4

0.4

0.5

100.0

98.9

0.3

0.2

0.6

100.0

100.0 100.0 100.0 100.0 100.0 100.0

t

100.0 10+3.0

9B.3 94.7

0.8 1.6

0,8 3.5

0,2 0.2

_ _ .

9B.B

0,3

0,3

0.6

100.0

98.B

0,3

0.3

0.7

100.0

98.8

0.4

0.3

0,5

100.0

98.7

0.4

0.5

0.4

100.0

99.0

0.3

0.2

0.4

100.0

96.3

1.0

2.3

0.5

100.0

99,3

0,2

0.4

0,1

100.0

99.5

0.2

0.2

0.1

100.0

99.6

0.2

0.2

0.1

100.0

99.3

0.3

0.3

0.2

100.0

99.0

0.2

0.6

0.2

100.0

99.4

0.1

0.4

0.1

White .................... .. ...................................... 100.0 100.0 I 100.0

99.5

0.2

0.2

0.1

100.0

98.3

0.3

1.2

0.2

100.0

99.5

0.2

0.2

0.1

100.0

95.8

0.4

3.5

0.3

100.0

99.7

0.1

0.1

0.1

100,0

97.8

0.2

1.B

0,1

100.0

99.1 98.3

0.5 1.0

0.3 0.5

0.1 0.2

All other... . .......... . . .......... . .......... . . ...... 100.0I 100.0

r

98.1

0.6

0.9

0.5

100.0

99.4

0.1

0.4

0.1

100.0

93,8

0.5

5.5

0.3

100,0

85.0

3.5

11.0

0.5

94.5

2.3

2.8

0.3

68.0

5.4

25.7

0.s

Black .. . .... . . .......... . . ... . . . ..... .. . . ..... ... ...

...

.. .

...

...

98.8

0.5

0,3

0,4

95,7

1.1

2.8

0.3

9B.2

0.3

1,3

0.2

99.2

0.3

0.3

0.2

95.1

0.4

4.2

0.2

97.6

0.2

2,0

0.1

99.4

0.1

0.4

0.1

92.7

0.5

6.5

0,3

...

...

...

... —.

...

...

...

...

lP[aces with 10,000 resldentsm more in 1960 for that year and 10,000 residents ormmein1970 for 1970.75.

‘includes all births inhospitals cmmstitutions and births attended by physicians in clinics, Avery Iafge proportion of births in hospitals are attended by physicians.

38
Table Il. Percent distribution of Iivebirths byattendant andplace ofdelivery and race: United States and each geographic division,

1973

[See Technical Notes]

Attendant and place of delivery

Area and race

United States

White .............................................. ............................................................ ...................... .

Black ......... ................................................................ ........................................................

New England

White ............................................................... ..................................... .............................

Black ................. ........ .. .............. ............ .................... ...................... .......... ........................

Middle Atlantic

White ......................................................................................................................... ........

Black ........................... ................ ............ .................... ................................ ......................

East North Central

White ....................................................................... .. ...... .................. ................................

Black .................................................................................................................................

West North Central

White ................................................................................ .... ................................. ............

Black ................. ................................................................................................................

South Atlantic

White .................................................................................................................................

Black ................ .................................................................... .............................................

East South Central

White ................................ ......................................... ................... .. ............ ...... .................

Black ................................ ......................................... ........................ ............... .................

West South Central

White ........................................ .............. ........ ...... .............................................................

Black ................................................ ................................ .................................................

Mountain

White ............................................................................................................. ....................

Black .... .......................................................... .............................................. ........ .............

Pacific

White ............................................................................... ..................................................

Black ...................................... .................... .......................... .............................................

Total

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

100.0

Physician

in

nospi -

tal 1

99.5

98.2

99.9

99.8

99.6

99.4

99.7

99.6

99.8

99.5

99.7

97.3

99.5

94.6

98.6

98.3

88.2

99.5

99.4

99.6

Physician

not

in

hospital

0.2

0.3

0.1

0.2

0.3

0.3

0.2

0.3

0.1

0.2

0.1

0.4

0.2

0.4

0.1

0.2

0.3

0.3

0.3

0.2

Midwife

0.2

1.3

0.0

0.0

0.0

0.0

0.0

0.2

0.1

2.1

0.2

4.8

1.1

1.3

0.2

0.0

0.0

0.0

Other

and

not

;peci -

fied

0.1

0.2

0.0

0.0

0.1

0.3

0.1

0.1

0.0

0.0

0.1

0.2

0.1

0.2

0.2

0.2

0.3

0.2

0.3

0.2

lIncludeS all bi~thS in ho5Pitals or inati~tions and births attended by physicians in clinks.. .+ VerY large ProPortion of blrt~ ‘n

hospitals are attended by physicians.

39
Table 12. Mean interval since Iastlive birth by Iive-birth order, educational attainment of mother, and race: total of 38 reporting States

and the District of Columbia, 1973

[ See Technical Notes]

Live-birth order and race

All races]

All second and higher order births ..................................................................

Second births ............................. ....................................................................................

Third births ....................................................................................................................

Fourth bi~hs ..................................................................................................................

Fifth births ............................... ......................................................................................

Sixth births and over ................. ...................... ...............................................................

White

All second and higher order births ................................. ........ .. .......................

Second births ........................ .........................................................................................

Third births ....... ........................ .....................................................................................

Fourth births ............................... .............. .....................................................................

Fifth births ............................................ .............. ...........................................................

Sixth births and over ......................................................................................................

Black

All second and higher order biflhs ........................ ..........................................

Second births ..................... .............................................................. ..............................

Third births .......................................................................... ..........................................

Fourth births ..................................................................................................................

Fifth births ............................... ......................................................................................

Sixth births and over ......................................................................................................

Total

43.4

39.1

46.6

49.6

51.2

47.2

43.8

39.2

47.5

51.0

52.9

48.5

41.9

39.3

42.4

44.5

45.7

44.8

Years of school completed by mother

I I 1 I

‘a19-’1I‘21

Mean interval in months

44.8

39.7

46.4

49.1

49.6

45.1

46.1

40.2

47.9

50.9

51.8

46.9

41.2

37.4

40.4

43.1

43.6

43.0

42.6

36.7

45.2

48.3

49.8

47.3

44.3

37.8

47.8

51.2

52.8

50.1

38.4

33.7

38.4

41.3

43.6

44.0

44.6

40.3

48.2

51.5

53.3

48.6

44.9

40.3

48.9

52.5

54.6

49.1

43.6

41.3

44.6

46.6

47.9

46.8

42.3

39.3

45.4

48.4

51.7

47.0

41.8

38.7

45.1

48.0

51.6

46.4

47.5

45.5

48.6

51.8

52.3

50.9

39.6

37.5

42.8

44.7

46.2

44.8

39.1

36.9

42.6

44.1

45.8

44.0

50.1

49.0

49.8

54.7

55.6

58.7

lInc]udes races other than white and black

40
Table 13. Percent of live births of 2,500 grams or less, by age of mother, interval since last live birth, and race: total of 40 reporting

States and the District of Columbia, 1973

[See Technical Notes]

Interval since last live birth and race

All”racesl ........................................................................ ..............

O months (plural deliveries) ....................... ................ .................. ..................

1-11 months ............................................................................... ...................

12-17 months ............... .................... ............................................................ .

18-23 months ........................................................................ ........................

24-35 months ................................. ............ ............................ .... ................ ...

3647 months ................. ...... .........................................................................

46-59 months ................................... ...... ............................ ............ ...............

60-71 months .................... .................... .. .................. ............................ ........

72 months or more ....................... ........................................................ .........

White ................................................ ......................... ........................

O months (plural deliveries) ............................................................ ...... ....... ..

1-11 months ..... ............................................ ............. ....................................

12-17 months .......................................................................................... ......

18-23 months ................. .................... .......................... .................................

24-35 months .............................................................. ..................................

3647 months ............ ....... ...................... ...................................... .................

48-59 months .................................................... ..................... .......................

60-71 months ... .......................................... ...... .............................................

72 months or more ........................................................................................

Black .......................................................... .................. .....................

O months (plural deliveries) .............. ............................................... ............. .

1-11 months ............................... ...................................................................

12-17 months ............ .................... ................................................................

18-23 months ........................................................................................... .....

24-35 months .................................... ........ ....................................................

3647 months ............................................... .. .............................................. .

48-59 months .... ............................................................................................

60-71 months ..................................... ........ .......................... .............. ...........

72 months or more .................... ...... ........ .................... ..................................

Total

7.3

55.3

20.8

8.4

6.3

5.5

5.3

5.8

6.2

7.5

6.2

52.9

17.5

6.9

5.3

4.7

4,6

5.1

5.5

6.6

13.2

66.5

29.8

14.5

11.8

10.9

10.5

10.4

10.4

11.9

Age of mother

Under

20

years

20-

24

years

25-

29

years

30- 35- 40-

34 39 44

years years years

13.2

68.2

27.0

12.0

9.4

9.3

9.7

10.1

12.0

14.1

10.6

65.7

22.3

9.1

7.0

7.0

7.6

5.9

13.2

19.6

18.1

73.4

34.7

17.5

14.3

13.7

12.8

13.8

11.5

7.7

7.5

57.3

20.0

8.2

6.4

5.6

5.9

6.5

6.5

8.0

6.3

54.8

17.4

6.8

5.4

4.9

5.0

5.4

5.4

5.9

13.1

67.5

28.0

13.7

11.4

10.6

11.0

11.0

9.9

12.8

6.1

-

51.6

16.8

6.9

5.1

4.8

4.6

5.2

5.9

7.1

5.5

50.4

14.1

6.0

4.6

4.3

4.2

4.7

5.3

6.1

11.7

60.9

27.5

12.9

10.1

10.0

9.2

9.2

10.0

12.0

6.6

50.7

18.2

7.2

5.5

4.9

5.0

5.7

6.3

7.0

6.0

48.2

17.4

6.5

4.9

4.4

4.6

5.2

5.8

6.3

11.6

63.0

21.6

11.6

10.1

9.6

10.1

10.8

10.9

11.1

7.9

50.5

17.7

9.0

6.7

5.8

6.1

6.3

6.7

8.2

7.1

47.4

16.2

7.9

6.4

5.2

5.5

5.6

5.5

7.5

12.4

61.8

22.2

13.0

9.2

9.3

10.4

10.7

13.0

13.0

8.7

52.9

23.3

6.2

7.3

7.1

6.6

7.3

7.7

8.9

8.0

51.5

15.9

5.5

5.7

6.5

5.9

6.3

7,3

8.5

12.2

71.0

43.8

8.4

15.7

10.4

10.3

11.4

10.3

11.6

lIncIud~ rat= other than white and black.

41
Table 14. Percent of births occurring less than 24 months since the previous Iive birth, by live-birth order, educational attainment of

mother, and race: total of 38 reporting States and the District of Columbia, 1973

[See Technical Notes]

Years of school completed by mother and race Total

27.1

33.6

33.1

24.5

24,0

24.6

33,2

24.4

25.4

31.7

30.0

23.3

23.6

24.5

30.4

23.5

34.9

39.7

40.8

31.0

26.1

21.6

40.6

29.7

2d

27.1

38.4

37.2

24.4

22.8

23.6

37.4

23.9

25.6

36.6

34.4

23.3

22.4

23.5

34.8

23.2

35.5

47.2

45.5

30.7

25.5

19.7

45.8

28.9

Live-birth order

3d

26.5

31.8

30.5

24.2

25.2

26.3

30.8

24.6

24.8

30.0

26.9

23.0

24.9

25.9

27.7

23.7

34.5

39.2

40.2

30.7

27.0

26.3

40.0

29.9

4th

26.6

29.3

29.1

24.4

26.1

27.4

29.1

25.0

24.6

27.3

25.4

22.9

25.8

27.6

26.0

23.9

34.6

37.2

37.8

32.2

27.5

22.5

37.7

31.2

5th

26.7

29.8

28.8

24.5

25.3

26.0

29.1

24.8

24.5

27.5

25.3

22.8

25.0

25.7

26.0

23.4

34.1

37.2

36.3

31.7

27.8

27.3

36.5

31.0

6th

and

>ver

30.2

33.3

31.3

27.7

27.6

28.6

32.1

27.8

28.0

31.3

27.6

26.4

28.2

29.3

29.2

27.0

34.5

36.4

35.7

32.1

25.2

16.2

36.0

30.9
Table 15. Percent of live births of 2,500 grams or less by outcome of last pregnancy, interval since termination of last pregnancy, and

race: total of 39 reporting States and the District of Columbia, 1973

[See Technical Notes]

Outcome and interval since last pregnancy

All live births resulting from second and higher order pregnancies ............................. .....................

1-11 months ........................................................ ..............................................................................................

12-17 months ....................................................................................................................................................

18-23 months ........... ................................................ .........................................................................................

24-35 months ....................................................................................................................................................

36-47 months ................................................................................ ................................ ....................................

48-59 months ....................................................................................................................................................

60 months or more .................................................................................................................. ..........................

Last pregnancy, live birth2 ................................................................................................................

1-11 months ......................................................................................................................................................

12-17 months ........................................................... .........................................................................................

18-23 months ....................................................................................................................................................

24-35 months ....................................................................................................................................................

3647 months ...................................................................................................... ..............................................

48-59 months ..................... ............................ ...................................................................................................

60 months or more ............................................................................................................................................

Last pregnancy, fetal death2 .......................... ............................... ....................................................

1-11 months ........................................................................................................ ..............................................

12-17 months ................................................. ...................................................................................................

18-23 months ....................................................................................................................................................

24-35 months ................................................................................ ....................................................................

3647 months ...................................... .................................................... ..........................................................

48-59 months ....................................................................................................................................................

60 months or more ....................................................................................... .....................................................

All

races 1

7.4

17.5

8.1

6.3

5.5

5.2

5.5

6.7

7.0

20.4

8.3

6.1

5.2

5.1

5.4

6.6

9.3

13.0

7.3

8.1

8.6

9.0

10.4

10.5

Nhite

6.3

14.4

6.6

5.3

4.7

4.5

4.8

6.0

6.0

17.2

6.7

5.1

4.5

4.4

4.7

5.8

8.1

11.1

6.5

7.2

7.6

8.0

9.4

9.7

Black

13.5

29.0

14.3

11.7

10.7

10.3

10.0

11.0

12.9

29.5

14.3

11.4

10.4

10.0

9.8

10.9

17.2

27.4

14.0

14.3

14.6

15.0

15.9

15.6

llncludes races other than white and black.

21ncludes zero months (plural births) and births for which the interval Was not stated.

43
Table 16. Estimated number of ii legitimate live births and illegitimacy ratios and rates, by race: United States, 1940,1950,1960, and 1965-75

[See Techm.al Notes]

Rate per 1,000 unmarried

women, 1544years2

Ratio per 1,000 total live

Estimated number]

All

races

btrths

White

73.0

65,4

63.9

60.4

56.1

56.6

54.7

53.3

46.7

44.4

39.6

22.9

17,5

19,5

—

Al I

races

—

White

All other All other All other

Year

Total Black Black

487,9

470,9

457.5

439.1

405.3

375.8

348.7

. . .

. . .

. . .

. . .

. . .

. . .

. . .

—

rotal

.

IIack

All

races Whrte

Total

441,7

427,3

416.9

402.6

373.3

349.3

325.1

312.0

293,8

276.5

263.2

215.8

179,6

166.3

— —

447,900

41 B,1OO

407,300

403,200

401,400

398,700

360,800

339,200

318,100

302,400

291,200

224,300

14? ,600

89,500

IB6,400

16B,500

163,000

160,500

163,600

175,100

163,700

155,200

142,200

132,900

123,700

82,500

53,500

40,300

261,600

249,600

244,300

242,700

237,600

223,600

197,200

183,900

175,s00

169,500

167,500

141,300

B8,100

49,200

249,600

238,800

234,500

233,300

229,000

215,100

189,400

. . .

. . .

. . .

. . .

. . .

. . .

. . .

142,5

132.3

129.8

123.7

112.9

106.9

100,2

96,9

90.3

83.9

77.4

52.7

39,8

37.9

24.8

24.1

24.5

24.9

25.6

26.4

25,0

24.4

23.9

23.4

23.5

21.6

14.1

7.1

12.6

11.8

‘11.9

‘12.0

12.5

13.9

13.6

13.2

12.5

12.0

?1.6

9.2

6.1

3.6

—

80,4

81.5

84.2

86.9

90.6

89.9

86.6

86.6

89.5

92.8

97.6

98.3

71.2

35.6

.

85,6

86.6

89.5

92.2

96.5

95.5

90.6

. . .

. . .

. . .

. . .

. . .

. . .

. . .

—

1Because estimates were rounded to the nearest hundred, figures by race may not add to totals.

2Rates were computed by relating total illegitimate births regardless of age of mother to unmarried women 15-44 years.

NOTE: The illegitimacy rates shown in this table for the years 1951.68 differ from those published m issues of Viral Statistics of the United States prior to 1969. The

rates shown here are based on a smoothed series of popukdirm estimates for unmarried women by race and age, which were not available when the prewously published rates

were computed.

44
APPENDIX

CONTENTS

Technical Notes ..... .............................................................................. ................................................... 46

Sources of Data ....................................................................................................... .......................... 46

Sampling Rates ..... .......................................................................... ............ ...................................... 46

Residence Classification .................... ......................................................................................... ....... 46

Geo~aphic Divisions mdRe@ons ..................................................................................................... 46

Population Bases .............................................................. ................................................................. 49

Race and Color ................................................. ................................................................................ 49

APPENDIX TABLE

I. Areas reporting educational attainment of parents, dates of Iastlive birth rmdfetal death, datelast

normal menses began (IMP), month of pregnancy prenatal care began, number of prenatal

visits, and Legitimacy status: each State, 1973-75 ....................................................................... .... 47

45
APPENDIX

TECHNICAL NOTES

Sources of Data

Statistics presented in this report are based

on information from certificates of live birth

filed throughout the United States. Additional

data and details concerning the technical aspects

of birth statistics are published annually by the

National Center for Health Statistics in volume

I of Vital Statistics of the United States. Table I

shows areas reporting specific items on the certificates of live birth.

Sampling Rates

Data for years prior to 1951 and for 1955

are based on the total file of birth records. Data

for 1951-54, 1956-66, and 1968-71 are derived

from 50-percent samples of birth records; data

for 1967 are based partly on 20-percent and

partly on 50-percent samples. Data for 1972-75

are based on information from two sources. For

6 States in 1972, 9 States in 1973, 16 States in

1974, and 23 States in 1975, statistics are based

on information from the total file of records

provided to the National Center for Health

Statistics through the Cooperative Health Statistics System. In 1972, these States were Florida,

Maine, Missouri, New Hampshire, Rhode Island,

and Vermont. In subsequent years, additional

States were added as follows: 1973–Colorado,

Michigan, New York (exclusive of New York

City); 19 74–Illinois, Iowa, Kansas, Montana,

Nebraska, Oregon, South Carolina; 19 75–

Maryland, Virginia, North Carolina, Tennessee,

Louisiana, Oklahoma, and Wisconsin. Statistics

for the remainder of the United States are based

on information obtained from a 50-percent

sample of microfilm copies of all certificates of

live birth.

Residence Classification

M data included in this report are tabulated

by place of residence. Births to U.S. residents

occurring outside this country have not been reallocated to the United States. Beginning in

1970, births to nonresidents of the United

States occurring in the United States have been

excluded from tabulations by place of residence.

Prior to that year, births occurring in the United

States to nonresident mothers were considered,

as births to residents of the place of occurrence.

All tables showing time series include data for

Alaska beginning with 1959 and for Hawaii beginning with 1960.

Geographic Divisions and Regions

The nine geographic divisions (as defined by

the U.S. Bureau of the Census) and their component States are as folIows:

Division States included

New England. . . . . . . .Maine, New Hampshire,

Vermont, Massachusetts,

Rhode Island, Connecticut

Middle Atlantic. . . . . .New York, New Jersey,

East North Central .,

West North Central . .

South Atlantic. . . . . .

Pennsylvania

.Ohio, Indiana, Illinois,

Michigan, Wisconsin

.Minnesota, Iowa, Missouri, North Dakota,

Nebraska, Kansas

.Delaware, Maryland, District of Columbia, Virginia, West Virginia, North

Carolina, South Carolina,

Georgia, Florida

46
Table 1. Areas reporting educational attainment of parents, dates of last live birth and fetal death, date last normal menses began (LMP),

month of pregnancy prenatal care began, number of prenatal visits, and legitimacy status: each State, 1973-75

Dates Date last Month of

of last normal pregnancy Number

live birth menses prenatal of prenatal

and fetal began care visits

death (LMP) began

Educational

Area attainment

of parents

Legitimacy

status

x

x

Alabama

Alaska x

I t I

x x

Arizona lx xl xl xl xl x

Arkansas I I I I I

x

California I xl xl xl I

Colorado x

Connecticut x

x x x x x

x x x

xl xl xl xl Dalaware xlx

District of Columbia lx xl xl xl xl x

Florida lx xl xl xl xl x

Georgia lx I xl xl xl lx

xl xl xl xl Hawaii x lx

Idaho I

4 xl xl xl Illinois x lx

Indiana x x x x x

lx

x x x x x

x x x x x

Iowa x

Kansas x

x x x x x

x x x x

Kentucky x

Louisiana x

x x x x x

lx x x

Maine x

Maryland lx

2X

x x x x x

x x x x x

x x x x x

x x x x x

Massachusetts x

Michigan x

Minnesota lx

Mississippi x

Missouri x

See footnotes at end of table.

47
Tablel. Areas reporting educational attainment ofparents, dates oflastlive binhand fetal death, date last normal manses began (LMP),

month of pregnancy prenatal care began, number of pranatal visits, and Legitimacy status: each State, 1973-75-Con.

I

Educational

Area attainment

of parents

Montana I x

Nebraska lx

Nevada x

New Hampshire x

New Jersey I x

New Mexico I

New York lx

North Carolina lx

North Dakota I x

Ohio x

Oklahoma x

Oregon x

Pennsylvania

Rhode Island x

South Carolina x

South Dakota x

Tennessee x

Texas

Utah I

x

Vermont x

Virginia x

Washington

West Virginia x

Wisconsin

Wyoming x

Dates Date last Month of

of last normal pregnancy Number

live birth

Legitimacy

menses prenatal of prenatal

and fetal began

status

care visits

death (LMP) bagan

x x x x

xl xl xl xl x

x x x x

x x x x x

xl xl xl xl x

xl xl xl I

d xl d d x

x x x

I

x x

x x x

x x x x x

x x x x x

x

x x x xl x

x x x x x

x x x x x

x x x x x

x x

xl xl xl xl x

x x x x

x x

x x x x x

x x x x x

1 xl xl x

x x x

I

x x

lDid not report in 1973.

Zcertificate ~equests on]y date of last live birth.

48
;ast South Central . . .Kentucky,Tennessee, Alabama, Mississippi

‘Jest South Central . . .Arkansas, Louisiana, Oklahoma, Texas

tiountain. . . . . . . . . . .Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada

‘acific . . . . . . . . . . . . .Washington, Oregon, Ca.hfomia, Alaska, Hawaii

The four geographic regions (as defined by

:he U.S. Bureau of the Census) are composed

>f the geographic divisions as foIlows:

Rep-on Division

iortheast . . . . . . . . . .New England, Middle Atlantic

Jorth Central . . . . . . .East North Central, West

North Central

South . . . . . . . . . . . . .SouthAtlantic, East South

Central, West South Central

West . . . . . . . . . . . . . .Mountain, Pacific

Population Bases

Populations used for computing illegitimacy

rates for the United States exclude the Armed

Forces overseas and persons living abroad but include the Armed Forces stationed in the United

States. Rates for 1940 and 1950 are based on

the population enumerated as of April 1 in the

censuses of those years. Rates for all other years

are based on the estimated midyear (July 1)

population for the respective years. For further

discussion see appendix I of the report, Vital

and Health Statistics, “Trends in Illegitimacy,

United States, 1940-1965,” Series 21, Number

15, from the National Center for Health Statistics.

Race and Color

In all cases, race or color refers to the child.

Tabulations by color have two categories–

“white” and ‘WI other.” Tabulations by race

show data separately for the black population.

000

+ U, S. GOVERNMENT PRNITNG OFFICE :1978 260-937/21

49
VITAL AND HEALTH STATISTICS Series

Series 1. Programs and Collection Procedures. –Reports which describe the general programs of the National

Center for HeaIth Statistics and its offices and divisions and data collection methods used and include

definitions and other material necessary for understanding the data.

Series 2. Data Evaluation and Method~ Research. –Studies of new statistical methodology including experimental tests of new survey methods, studies of vital statistics collection methods, new analytical

techniques, objective evaluations of reliability of collected data, and contributions to statistical theory.

Series 3. Analytical Studies. –Reports presenting analytical or interpretive studies based on vital and health

statistics, carrying the analysis further than the expository types of reports in the other series.

Series 4. Documents and Committee Reports. – Final reports of major committees concerned with vital and

health statistics and documents such as recommended model vital registration laws and revised birth

and death certificates.

Series 10. Data From the Health Interview Survey .-Statistics on illness, accidental injuries, disability, use of

hospital, medical, dental, and other services, and other health-related topics, all based on data collected

in a continuing national household interview survey.

Series 11. Data From the Health Examination Survey and the Health and Nutn”tion Examination Survey. –Data

from direct examination, testing, and measurement of national samples of the civilian noninstitutimsalized population provide the basis for two types of reports: (1) estimates of the medically defined

prevalence of specific diseases in the United States and the distributions of the population with respect

to physical, physiological, and psychological characteristics and (2) analysis of relationships among the

various measurements without reference to an explicit fkite universe of persons.

Series 12. Data From the Institutionalized Population Surveys. –Discontinued effective 1975. Future reports from

these surveys will be in Series 13.

Series 13. Data on Health Resources Utilization. –Statistics on the utilization of health manpower and facilities

providing long-term care, ambulatory care, hospital care, and family planning services.

Series 14. Data on Health Resources: Manpower and Facilities. –Statistics on the numbers, geographic distribution, and characteristics of health resources including physicians, dentists, nurses, other health

occupations, hospitals, nursing homes, and outpatient facilities.

Series 20. Data on Mortality. –Various statistics on mortality other than as included in regular annual or monthly

reports. Special analyses by cause of death, age, and other demographic variables; geographic and time

series analyses; and statistics on characteristics of deaths not available from the vital records based on

sample surveys of those records.

Series 21. Data oh Natality, Marriage, and Divorce. –Various statistics on natality, marriage, and divorce other

than M included in regular annual or monthly reports. Special analyses by demographic variables;

geographic and time series analyses; studies of fertility; and statistics on characteristics of births not

available from the vital records based on sample surveys of those records.

Sm”es 22. Data Frorrs the National Mortality and Natality Survey s.-Discontinued effective 1975. Future reports

from these sample surveys based on vital records will be included in Series 20 and 21, respectively.

Series 23. Data From the National Survey of Family Growth. –Statistics on fertility, family formation and dissolution, family planning, and related maternal and infant health topics derived from a biennial survey

of a nationwide probability sample of ever-married women 15-44 years of age.

For a list of titles of reports published in these series, write to: Scientific and Technical Information Branch

National Center for Health Statistics

Public Health Service

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