.

Intewal Between

Binils:

UnitedStates,

1970-77

An analytical review of recent trends and

differentials in the interval between the current live birth and previous live birth or fetal

death.

Data From the National Vital

statmhSy%t’un

sorb21, No. 39

DHHS Publication No. (PHS) 81-1917

U.S. Department of Health and Human

Services

Public Health. Service

Office of Health Research, Statistics, and

Technology

National Center for Health Statistics

Hyattsville, Md.

Aqgust 1981
Library of CongressCataloging in Publication Data

Spratley, Ernell

Interval between births, United States, 1970-77,

(Vital and health statistics. Series 21, Data from the national vital

statistics system ; no. 39) (DHHS publications ; no (PHS) 81-1917)

References: CJ.24

1. Birth intervals-United States–statistics, 1. Taf fel, Selma,

jOiIIt author. Il. Title. Ill. Saries. IV. series: DHHS pub.

Iication ; no. (PHS) 81-1917. [DNLM: 1. Birth intervals.

W2A N148vu no.39/ HB902 161]

HA21 1.A3 no. 39 [H B902] 312’.1’73s 81-9575

IS8N 0-8406 -0223-5 [312’.1’73] AACR2

For sale by the Superintendent of Documents, U.S. Government Printing office, Washington, D.C. 20402
National Center for Health Statistics

DOROTHY P. RICE, Director

ROBERT A. ISRAEL, Deputy L?irector

JACOB J. FELDMAN, Ph.D., Associdte Director for Analysis

and Epidemiology

GAIL F. FISHER, Ph.D.,Associate Director for the

Cooperative HealthStatistics System

GARRIE J. LOSEE, Associate Director for Data l?ocessing

and Services

ALVAN O. ZARATE, Ph.D., Assistant Director for

InternationalStatistics

E. EARL BRYANT, Associate Director for Interview and

Examination Stan”sn”cs

ROBERT C. HUBER, Associate D&ectorfor Management

MONROE G. SIRKEN, Ph.D., Associate Director for Research

and Methodology

PETER L. HURLEY,Associate Director for Vitaland Health

GrreStatistics

ALICE HAYWOOD, Information Officer

Division of Vital Statistics

JOHN E. PATTERSON, Director

ALICE M. HETZEL, Deputy Director

ROBERT L. HEUSER, M.A., Chiej iVatali~ StatzkticsBranch

JOSEPH D. FARRELL, Chief Computer Applications Staff

MABEL G. SMITH, Chie~ Statistical Resources Branch

.,.

Libraxy of Congress Catalog Card Number 81-9575
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........~-..........”

Summary offindings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Interval since lastlive birth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ageofmother . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Live-birth order. . : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Trends inageand birth-order intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Race . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Education ofmother . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Interval since termination oflastpregnancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Age of mother . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Race . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Education ofmother . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Low birth weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

Listofdetailed tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Technical notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

List of Text Figures

1.

2.

3.

4.

5.

6.

7.

Mean interval since last live birth, by age of mother and race: Total of 43 reporting States and the District of Columbia,

1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .....................”.... . ...”

Observed and adjusted mean interval since Iastlivebirth, by live-birth order: Total of43reportingStates andthe District

ofColumbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mean interval since lastlivebirth,by race: Total of reportingareas, 1970-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Percent of live births occurring within 18 months of the preceding live birth, byageof mother and rece:Totalof43

reporting States andtheDistrict ofColumbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Percent of live births occurring within24 months of the preceding Iivebirth, by educational attainmentof mother and

race: Total of43 reporting States andthe DistrictofColumtia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mean interval since termination of last pregnancy, byage ofmother and outcome oflast pregnancy: Total of43 reportingStates andthe Districtof Columbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Percent of infants of low birth weight, by interval since termination of last live birth and Iastfetal death and educational

attainmentof mother: Total of41 reportingStates andthe District ofColumbia,1977 . . . . . . . . . . . . . . . . . . . . . . .

List of Text Tables

A. Cumulative Percent distribution of live births by interval since last live birth, according to race: Total of reporting areas,

1970and 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

2

3

3

4

4

6

8

14

14

15

15

16

19

23

24

43

4

6

9

10

12

15

22

3

...

Ill
B. Percent distribution of Iive births by interval since last Iive birth, according to age of mother and race: Total of 43 reporting States andthe District of Columbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. . . . . . . . . . . . . . . . . . . . .

C. Absolute and percent change in mean interval since last live birth between 1970 and 1977, by age of mother and livebirth order: Total of reporting areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

D. Percent distribution of live births by live-birth order, according to age of mother: Total of reporting areas, 1970and

1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

E. Mean interval since last live birth, by age of mother andlive-birth order: Total of43reporting States andthe Distfictof

Columbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

F. Observed mean interval since last live birth for 1970 and 1977, andadjusted mean interval since lastlive birth forll977,

byageof mother: Totalofreporting areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .,..m...m.m.

G. Observed mean interval since last live birth forwhite Mmhs, andobsewed andadjusted mean intewal since last live birth

for black births, by live-birth order: Total of43reportingStates and the Districtof Columbia, 1977 . . . . . . . . . . . . . .

H. Mean interval since last live birth, by age of mother, educational attainment of mother, and race: Total of reporting

areas, 1970and 1977..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

J. Median age of mother at first birth, by educational attainment of mother andrace: Total of41reporting Statesan(d the

DistrictofColumbia, 1977..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

K. Mean interval since last live birth, by educational attainment of mother, Iive-birth order, ageofmother, andrace: -rotal

of41reporting States and the District of Columbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

L. Observed mean interval since last live birth for1970 and1977, andadjusted mean interval sin@ lastlive tirthforl977,

byeducational attainment of mother: Total of reporting areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

M. Percent of live births where the preceding pregnancy had terminated as a fetal death, by age of mother and race: Total of

43reporting States andthe District of Columbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

N. Cumulative percent distribution of live births by interval since termination of last pregnancy, according to outcome of

last pregnancy: Total of 43 reporting States and the District of Columbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0. Percent of live births where the preceding pregnancy had terminated as a fetal death, by educational attainment of

mother and race: Total of 41 reporting States and the District of Columbia, 1977. . . . . . . . . . . . . . . . . . . . . . . ,, . . .

P. Percent of live births occurring within 18 months of the termination of the preceding pregnancy, by outcome of last

pregnancy, educational attainment of mother, and race: Total of 41 reporting States and the District of Columbia,

1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Q. Mean interval since termination of last pregnancy, by outcome of last pregnancy, age of mother, and race: Total of

reporting areas, 1970and 1977.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

R. Mean interval since termination of last pregnancy, by outcome of last pregnancy, live-birth order, and race: Total of reporting areas, 1970and 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

S. Percent of infants of low birth weight, by outcome of last pregnancy, interval since termination of last pregnancy,, and

race: Total of43 reporting States andthe District of Columbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

T. Percent of full-term infants of low birth weight, by outcome of last pregnancy, interval since termination of last lpregnancy, and race: Total of 41 reporting States and the District of Columbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . .

U. Percent of infants of low birth weight, by age of mother, interval since last live birth, and race: Total of 43 reporting

States andthe District of Columbia, 1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

7

7

8

8

10

11

12

13

13

14

14

16

16

17

18

19

20

21

Symbols

--- Data not available

. . . Category not applicable

Quantity zero

0.0 Quantity more than zero but less than

0.05

z Quantity more than zero but lessthan

500

*

Figure does not meet standards of

reliability or precision
Interval Between Births

by Ernell Spratleya and Selma Taffel, Division

of Vital Statistics

Introduction

How closely births are spaced is an important

determinant of the rate of population growth and has

a strong bearing on maternal and infant health. For

these reasons, items requesting the dates of the

mother’s last live birth and last fetal death were

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

in 1968 to provide information on child spacing.

These items have been used to derive the interval

between the date of the current live birth and the

termination of the last pregnancy and to determine

whether the preceding pregnancy had terminated as a

live birth or a fetal death.b

This report analyzes recent trends and differentials in the interval between the current live birth and

previous live birth or fetal death. It also presents a

discussion of the association between low birth

weight (2,500 grams or 5% pounds or less) and the

length of time between deliveries.

aFormerly with the Division of Vital Statistics.

bFetal deaths in this report include all losses of conception, both spontaneous and induced, regardless of the gestational period. It is not possible to distinguish between induced and spontaneous fetal losses prior to

the 1978 revision of the Standard CertMcate of Live Birth. The number of fetzd deaths before and after 20 weeks of gestation are noted

separately on the revised oertifkate.

Data are based on information obtained from the

live-birth certificates of the States that reported the

dates of the last live birth and fetal death for the

years 1970-77. A listing of the States that comprised

the reporting area for these years as well as a description of the method of determining the interval

between the current live birth and the previous delivery are given in the Technical notes of this report.

Trend data cover the years 1970-77 and focus on

the changes in the interval between successive deliveries according to social and demographic factors

available from the birth certificate-maternal age, livebirth order, race, and mother’s educational attainment. Although there were changes in the number of

States comprising the reporting area during this

period, the effect of these changes on the comparison

of statistics for 1970 and 1977 is minimal. For further discussion of this point, see the Technical notes.

The health-related aspect of interval length is considered in terms of variations in low birth weight and is

discussed only for the year 1977.

Because the data shown in this report are derived

from individual birth certi13cates, the figures shown

technically refer to numbers of births rather than to

numbers of mothers. However, for ease in presentation, the terms “mothers” and “women” rather than

“births” are occasionally used.
Summary of findings

The period 1970-77

declining fertility. Both

reached record low levels

was a

birth

time of generally

and fertility rates

in the years 1972-1976.

Concomitantly, there was a gradual lengthening in the

time between live births. By 1977, the mean interval

between the mother’s current birth and her previous

live birth was 45.5 months, about 4 months longer

than the average interval of 41.8 months in 1970. If

the age distribution of mothers giving birth in 1977

had remained the same as it was in 1970, there would

have been an even greater increase in the mean interval to 46.4 months. Coincident with the lengthening

of the live-birth interval, there was a sharp decline in

the proportion of children born within 18 months of

a previous live birth (from 17.3 to 13.4 percent) and

an increase in the proportion of children born 6 years

or more after a previous birth (from 13.2 to 16.3

percent).

Women of all ages, educational attainment, and of

both major racial groups spaced their children farther

apart in 1977 than in 1970. Increases in the average

interval between live births were substantially greater

for older than for younger women, for better educated women than for women with less than a high

school education, and for black than for white

women.

In 1977 as in previous years, there was a strong

association between maternal age and the mean interval between live births; each increase in age was associated with a lengthening in the mean interval. Births

to teenage mothers in 1977 followed a previous birth

by an average of 23 months; for women aged 25-29

years, the average birth interval increased to 45

months; and for women in the advanced childbearing

years (45-49 years of age), the average interval since

the previous birth was 9 years. The mean interval

between first and second births (43 months) was less

than the average interval following second or higher

order births, reflecting the younger ages of mothers

bearing a second child.

Although the average interval between black

births was longer than between white births in 1977

(a reversal from 1970), a larger proportion of black

babies (16 percent) than of white babies ( 11 percent)

was born within 1Y2years of a previous live birth.

2

Increasing educational attainment for white

mothers was associated with a closer spacing of births,

but better educated black mothers spaced their children farther apart than those with minimal schooling.

Among white mothers with less than 9 years of

school, the mean interval between live births was 46.8

months, but only 41.3 months for mothers who had

completed college. For comparable levels of educational attainment, the spacing between black births

rose from 45.9 to 55.2 months.

Regardless of maternal age or birth order of the

child, women were more likely to bear a child sooner

after a fetal death than after a live birth. About twothirds of the live births that followed a fetal death

occurred within 2 years of the fetal death, but only

about one-fourth of the births that followed a live

birth were this closely spaced.

The mean interval between deliveries was about 2

months longer for black than for white births

whether or not the preceding pregnancy had terminated as a live birth or as a fetal death.

Close spacing of births was found to be highly

associated with an increased risk of a low-birthweight outcome. In 1977, 19.2 percent of the births

occurring within 1 year of a previous live birth

weighed 2,500 grams or less, or about 3-4% times the

proportion observed for longer interbirth intervals.

The percent low birth weight was lowest (4.2 percent) when the interval between live btiths was 2-4

years, and this period was the optimum interval for

all maternal ages and for most levels of educational

attainment.

To a lesser extent, births closely following a fetal

death had a higher risk of a low-birth-weight outcome

than when the interbirth interval was more than 1

year. The incidence of row birth weight wals highest

(1 1.6 percent) for births following a fetal death

within 1 year and lowest (6.6 percent) when the

interval was 12-23 months. For all levels of educational attainment, a far higher level of low birth

weight was found among very closely spaced live

births than when the current birth closely followed a

fetal death.
Interval since last live birth

As the fertility of American women moderated

during the period from 1970 to 1977, the interval

between successive live births gradually increased. As

shown in table 1, the mean interval rose steadily from

41.8 months in 1970 to 45.5 months in 1977.

In 1977, as in 1970, about one-half of all second

or higher order infants were b.cm within 3 years of a

previous live birth. However, there was a noticeable

decline in the proportion of children born after the

relatively short interval of less than 18 months (from

17.3 percent in 1970 to 13.4 percent in 1977)

(table A). Concomitantly, a larger proportion of children born in 1977 (16.3 percent) than in 1970 (13.2

percent) followed a previous birth by 6 years or

more. These changes in the interval between successive children probably reflect in part the welldocumented increasing availability, acceptance, and

usage of highly effective means of family pkmning.l’3

Age of mother

The mother’s age is probably the most important

factor associated with variations in the length of time

between live births. Women who start childbearing at

young ages are likely to have additional children more

rapidly and to have more unwanted births than

women who postpone childbearing to later ages.475

As shown h figure 1, the average interval between

live births increased progressively as maternal age increased. Births to mothers less than 20 years old followed a previous birth by an average of 23 months,

compared with an average interbirth interval of 45

months for women in their mid- and late twenties and

of 9 years for women 45-49 years old. These differences are not primarily a reflection of the number of

previous live births since the same pattern of lengthening interbirth interval with increasing age is seen for

each birth order (table 1).

The large differences in average interbirth interval

among different age groups reflect an overall shift in

the distribution of births towards longer intervals

with advancing age. For example, 38 percent of

second and higher order births to mothers in their

early twenties were born 3 years or more after a

previous child, compared with 80 percent of. the

births to women 40 years of age or older. Over half of

Table A. Cumulative percent distribution of live births by interval sinca last live birth, according to racrx Total of reporting areas, 1970 and 1977

[Refers only to second and hioher order live births]

. 1977 1970

Interval All White Black All White Black

racesl racesl

Omonths (plural births) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 1.3 1.6

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.0 2.7 4.3}

3.3 2.9 5.6

12-14 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . ’. . . . . . . . . 7.8 7.1 10.7 10.2 9.2 15.7

16-17 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4 12.5 17.1 17.3 16.0 24.8

18-20 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.7 18.8 23.5 24.4 22.9 32.9

21-23 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26.3 25.5 29.3 31.6 30.1 40.1

24-29 months . . . . . . . . . . . . . . . . . . . . . . ..- . . . . . . . . . . . . 38.4 38.1 38.5 44.5 43.1 51.9

30-35 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49.4 49.5 48.3 55.2 54.1 60.9

3647months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65.5 66.1 62.1 70.6 70.0 73.6

48-59 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76.3 77.0 72.7 80.3 79.9 82.1

60-71 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.7 84.3 80.8 86.8 86.5 87.9

72monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100.0 100.0 100.0 100.0 100.0 100.0

1ln~ludesracesother than whita and black.

3
-. a. All races

.zzz.white

— Black

+

Under 20-24 25-29 30-34 35-39 4044 45-49

20 years years years years years years years

Age of mother

NOTE: Refars only to second and higher order live births.

Firsura 1. Mean interval since last live birth, by age of mother and race:

Total of 43 reporting States and tha District ;f Columbia, 1977

this latter group of women gave birth 6 years or more

after their last live birth (see table B).

Teenage mothers comprise a small proportion of

women having second and higher order births (only

6 percent of the total in 1977). However, it is likely

that the short birth intervals predominant among

these very young mothers have a profound effect on

the family’s economic welfareG as well as increasing

the risk of an unfavorable pregnancy outcome.7 The

adverse effects on infant health associated with the

close spacing of births are discussed in the section

entitled “Low birth weight.”

The lengthening of the birth interval with increasing maternal age may be due to several factors. The

first and most obvious is that mothers in their

younger childbearing years have not had the time

available to experience long intervals. Another explanation advanced by some researchers is that part of

the increase in live-birth interval for older mothers is

due to the higher rates of fetal loss and declining

fecundity that are associated with advancing ages ~g

The very long intervals for older women may also reflect family planning failures.

Live-birth order

The average interval between births for each birth

order is greatly influenced by the distribution of

births by maternal age. Therefore, much of tlhe difference between birth orders reflects differences in the

proportion of older and younger mothers. The greater

the proportion of births to older mothers comprising

a particular birth order, the longer the average interval will be. Thus the average interval following a third,

fourth, fifth, or sixth order birth (where older

mothers predominate) was about 50 months in 1977

compared with a 43-month average interval following

first births (table 1). x

If the mothers’ ages were similarly distributed for

each birth order, then the length of the average

interval would decrease between each successive birth

after the third child.c As shown in figure 2, this

diminution in average interval between higher order

births is quite substantial when the effects c}fage are

eliminated. It has been hypothesized that a shortening in interval after the third child may be a reflection

of the childbearing experience of a highly selected

group of women who are not especially effective in

controlling births after having the desired number of

children. 10

Trends in age and birth-order intervals

Mothers of all ages spaced their children-farther

apart in 1977 than in 1970, but the increase in the

average interval between ‘live births was greater for

older than for younger mothers. The average interbirth interval for mothers 40 years or older increased

by 13-15 months between 1970 and 1977 (1 5-16

percent) compared with ~increases of 2-4 months

(1O-13 percent) for mothers less than 25 years of age

(table C).

Based on probable completed fertility, the increases between 1970 and 1977 in the average

cThe direct method of standardization was used for this procedure-see

Technical notes for a more complete discussion.

4
Table B. Percent distribution of live births by interval since last live birth, according to age of mother and race: Total of 43 reporting States and the

District of Columbia, 1977

[ Refers only to second and higher order live births. Excludes the later born in multiple deliveries]

Age of mother

interval and rata

All Under

20

20-24 25-29 30-34 35-39 4&49

ages

years

years years years years years

All racesl

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60-71 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

72 monthsand over . . . . . . . . . . . . . . . . . . . . . . . . .

White

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60-71 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

72monthsand over . . . . . . . . . . . . . . . . . . . . . . . . .

Black

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . . . . ..i.

18-23 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60-71 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

72monthsandover . . . . . . . . . . . . . . . . . . . . . . . . .

100.0

1.6

10.6

13.0

23.5

16.3

10.9

7.5

16.5

100.0

1.4

10.0

13.1

24.4

16.8

11.0

7.4

16.0

100.0

2.7

13.1

12.3

19.3

14.0

10.8

8.2

19.5

100.0

6.3

29.6

24.5

27.4

9.4

2.4

0.4

0.1

100.0

6.0

30.0

25.2

28.0

8.6

1.9

0.3

0.1

100.0

6.6

28.5

23.1

26.5

11.0

3.5

0.7

0.1

100.0

2.2

14.3

16.7

28.5

18.3

10.9

5.5

3.6

100.0

1.9

14.0

17.2

29.8

18.6

10.5

5.0

3.0

100.0

3.0

14.6

14.5

23.4

17.6

12.8

7.7

6.4

100.0

1.0

7.9

11.5

23.7

17.7

12.4

9.2

16.5

100.0

0.9

7.7

11.9

24.9

18.4

12.4

8,9

15.0

100.0

1.7

8.6

8.6

15.9

13.7

12.6

11.6

27.4

100.0

0.8

6.0

8.7

17,8

14.9

11.7

9.6

30.7

100.0

0.7

5.7

8.8

18.4

15.5

11.9

9.5

29.6

100.0

1.2

7.1

7.3

12.5

10.4

9.7

9.9

41.9

100.0

0.7

5.6

7.3

13.0

10.2

8.7

8.0

46.4

100.0

0.6

5.2

7.4

13.3

10.3

8.7

8.0

46.4

100.0

1.2

6.9

6.1

11.3

8.8

8.0

7.8

49.9

100.0

0.4

3.7

5.2

10.7

8.1

7.2

7.4

57.3

100.0

0.4

3.3

5.0

10.6

8.1

7.3

7.4

58.0

100.0

0.6

4.5

5.9

10.5

7.5

7.2

7.4

56.4

1 ,nclude~ races othar than whita and black.

number of months between births are probably

understated for many age groups. This understatement exists because at any given time before the end

of the childbearing period all births of a particular

order have not occurred, and there is evidence that

births for some age groups were being postponed toa

greater extentin 1977 than in1970. Forexample, by

the end of 1970, women aged 25-29 years in that

year had already given birth to51 8second births per

l,OOOwomen.This figurewasfarhigher thanthe383

second births for women aged 25-29 years in1977. If

we assume that bothgroups ofwomen will eventually

have the same number of second births, then there

will be far more second births at older ages towomen

who were 25-29 years in 1977 than to their 1970

counterparts. Thus the increase of5.6 months (from

42.Oin 1970 t047.6in 1977) in the average number

of months between first and second births for women

aged 25-29 years is probably an understatement of

the eventual increase, which canonly be ascertained

at the end of the childbearing period of these two

groups of women.

The increases between 1970 and 1977 in the

average interval for each age group can be partly

explained by the lengthening of the interval for some

birth orders (table C) as well as a decline during this

period in the total number of children that women

had ever borne. A far larger proportion of all second

and higher order children born in 1977 than in 1970

were second and third order births (table D). Because

the mean interval since the last live birth for these

low orders for each maternal age group is generally

longer than for the higher orders (table E), the

increases in mean interval between 1970 and 1977 for

each age group to some extent reflect the larger propofiion of low-order births.

Table F shows the observed mean intervals shice

the last live birth by age of mother for 1970 and

1977 and hypothetical intervals that would have

occurred in 1977 if the birth-order distribution

within each age group had remained constant during

this period. From this table, it can be determined that

38 percent of the increase in the mean interval for

women aged 25-29 years, 86 percent of the increase

5
-.

**

-

Adjusted for differences in age of mother - +

I I I [ I I I

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

and

Live-birth order ovar

NOTE: Refers only to second and higher order live births.

Figure 2. Observed and adjusted mean intewal sinca last live birth, by

live-birth order: Total of 43 reporting States and tha District of

Columbia, 1977

for women aged 30-34, and 51 percent of the increase

for women aged 35-39 resulted from this shift to

lower birth orders. For other age groups, changes in

birth-order distribution accounted for 15 percent or

less of the change in mean interval.

An overall picture of changes between 1970 and

1977 in the mean interval by maternal age and birth

order is shown in table C. Women in the oldest years

of childbearing, particularly those having higher order

births, were spacing their children farther apart in

1977 than in 1970. In contrast, women in their teens,

twenties, and early thirties for the most part were

6

reducing the interval bet ween high-order births during

this period. A far smaller proportion of women in

these younger childbearing ages went on to have

fourth or higher order births in 1977 than in 1970 (9

percent compared with 15 percent). It seems probable, therefore, that the shortening in the interval

between high-order births to young women is reflecting to a large extent the birth experiences of women

who either desired large families or who were unable

to practice effective fertility control.

The increase in the mean interval from 41.8

months to 45.5 months between 1970 and 1977

cannot be attributed to a change in maternal age at

the time of delivery. Indeed, if the age distribution

had remained constant during this period, the average

interval would have risen even more, to 46.4 months,

because

aged 35

mothers

1970.

Rade

there were proportionately fewer mothers

years or more and a larger concentration of

less than 30 years of age in 1977 than in

Historically, the overall level of childbearing has

been higher for the black than for the white

population. This has been manifest in higher birth

rates, and until 1975, in shorter average intervals

between successive live births (figure 3).

Between 1970 and 1977, the average interbirth

interval increased by 8 months for black births (22

percent), but by only 3 months (7 percent) for white

births. By 1974, racial differences had virtually

disappeared, and recently, the direction of the racial

difference has reversed (figure 3 and table 1). In

1977, the average interval was 47.3 months for black

births compared with 45.2 months for white births.

The greater overall increase from 1970 to 1977 in

interbirth interval for black than for white births is a

result of the larger increases experienced by all black

maternal age groups, as well as the more pronounced

shift towards lower birth orders observed for black

than for white mothers of all ages.

Another way of contrasting changes in childspacing between black and white births during the

1970’s is to compare the proportion of births for

each racial group that followed a previous birth

within a specified period. For example, in 1970,

one-third of all black births of second and higher

order occurred less than 21 months after a previous

birth; by 1977, this proportion had dropped to

slightly less than one-fourth. The comparable decline

for white births was from 23 to 19 percent (table A).

The substantial lengthening of interbirth intervals

for black mothers during the early 1970’s can be

partly related to the increased usage of the more

effective forms of contraception. Between 1970 and

1973, the proportion of black married women using

the pill, an IUD, or where one partner had a sterilizing operation, increased from 39 percent to 49 per-
Table C. Absolute and percent change in mean interval since last live birth between 1970 and 1977, by age of mother and live-birth order: Total of

reporting areas

[Refers only to second and-higher order live births]

Age of mother

Ltve+.sirth order All Under

20

20-24 25-29 30-34 35-39 40-44 45-49

ages

years

years years years years years years

All second and higher order births . . . . . . . . 3.7 2.1

Second births . . . . . . . . . . . . . . . . . . . . . . 6.3 2.3

Third births . . . . . . . . . . . . . . . . . . . . . . . 3.1 0.8

Fourth births . . . . . . . . . . . . . . . . . . . . . . 1.6 -0.7

Fifth births . . . . . . . . . . . . . . . . . . . . . . . 2.9 -1.5

Sixth births . . . . . . . . . . . . . . . . . . . . . . . 3.6 ●

Seventhbirths . . . . . . . . . . . . . . . . . . . . . 5.5 *

Eighth andhigher order births . . . . . . . . . . . 4.9 *

Absolute change (in months) 1

3.9 4.2 3.5 7.8 13.1 14.5

4.7 . 5.6 1.2 –1.9 1.3 17.1

1.8 1.9 1.0 0.1 5.9 15.1

0.1 -0.4 0.1 5.8 12.4 15.1

-0.8 -1.3 0.6 7.2 16.2 9.9

-0.2 -1.5 -0.4 6.0 13.6 17.5

-2.3 -0.7 0.2 4.7 18.7 22.9

–1.1 0.7 -0.9 3.5 9.2 17.0

Percent changel

Allsecond andhigher order births . . . . . . . . 8.9 10.0 13.0 10.2 6.4 11.3 15.9 15.3

Secondbirths . . . . . . . . . . . . . . . . . . . . . . 17.2 10.8 15.2 13.3

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

2.1 -2.4 1.2 13.0

6.9 4.0 6.2 4.3 1.6 0.1 5.0 10.6

Fourth births . . . . . . . . . . . . . . . . . . . . . . 3.4 -3.6 0.4 -1.0

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

0.2 7.3 11.8 12.0

6.0 -7.5 -3.2 -3.6 1.2 10.2 17.8 9.1

Sixth births . . . . . . . . . . . . . . . . . . . . . . . 7.8 *

-0.9 -4.7 -0.9 10.0 17.0 17.0

Seventhbirths . . . . . . . . . . . . . . . . . . . . . 12.6 ●

-9.5 -2.5 0.5 8.8 28.0 24.8

Eighth andhigher order births”. . . . . . . . . . . 12.6 *

-4.0 2.7 -2.7 8.6 18.1 27.8

I Positive numbars indicata an incraaw in the mean interval batween 1970 and 1977.

Table D. Percent dimribution oflivetitihs byliv&birth order, according toa@of mother: Totelof reporting areas,1970and 1977

[Refers only to second and higher order births. Excludes the later born in multiple deliveries]

Age of mother

~ Live-birtho rderandyear

All

Under

20

20-24 25-29 30-34 35-39 40-44 45-49

ages

years

years years years years years years

1977

Allsecond andhigher ordar births . . . . . . . 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0

Secondbirths . . . . . . . . ..(. . . . . . . . . . . 56.0 86.0 70.8 55.4 37.5 20.1 10.9 6.0

Third births . . . . . . . . . . . . . . . . . . . . . . 26.0 12.4 22.3 29.2 31.7 23.3 13.6 7.8

Fourth births . . . . . . . . . . . . . . . . . . . . . 9.9 1.4 5.3 10.1 16.3 19.6 14.8 9.7

Fifth births . . . . . . . . . . . . . . . . . . . . . . 4.0 0.2 1.2 3.4 7.5 13.8 14.9 12.1

Sixth births . . . . . . . . . . . . . . . . . . . . . . 1.9 0.0 0.3 1.2 3.7 8.8 12.2 12.2

Sevanth births . . . . . . . . . . . . . . . . . . . . . 1.6 0.0 0.1 0.4 1.8 5.7 9.5 11.6

Eighth andhigher order births . . . . . . . . . . 1.2 0.0 0.0 0.2 1.7 8.7 24.1 40.7

1970

Allsecond andhigher order births . . . . . . . 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0

Secondbirths . . . . . . . . . . . . . . . . . . . . . 44.6 83.9 65.4 40.3 19.9 11.3 7.9 4.9

Third births . . . . . . . . . . . . . . . . . . . . . . 25.8 13.6 24.1 31.6 26.3 17.4 12.2 10.7

Fourth births . . . . . . . . . . . . . . . . . . . . . 13.5 2.1 7.4 15.9 21.6 19.0 15.3 12.3

Fifthbirths . . . . . . . . . . . . . . . . . . . . . . 0.3 2.2 7.1 13.9 16.2 14.7 11.2

Sixth births . . . . . . . . . . . . . . . . . . . . . . H 0.0 0.6 3.0 8.1 11.6 12.4 11.9

Saventh births . . . . . . . . . . . . . . . . . . . . . 2.1 0.0 0.2 1.3 4.6 8.2 9.8 9.8

Eighth andhigher order births . . . . . . . . . . 3.1 0.0 0.1 0.9 5.5 16.2 27.7 39.3

7
Table E. Mean intemlsin@ laWiive birth, bya~ofmother endlive-bi~h order: Total of43reporting States andthe Distriti of Colt! mbia, l977

~R@fers onW to second and higher order live births]

Age of mother

Live-birth order All Under

20 20-24 25-29 30-34 35-39 40-44 45-49

q7es

years

years years years years years years

Allsecond andhigher order births . . . . . . . . . . 45.5 23.2 33.9

Second births . . . . . . . . . . . . . . . . . . . . . . . . . . 43.0 23.6 35.7

Thirdbi~hs . . . . . . . . . . . . . . . . . . . . . . . . . . . 48.1 20.7 30.8

Fourth births . . . . . . . . . . . . . . . . . . . . . . . . . . 49.3 18.8 26.4

Fifth births . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.3 18.5 24.0

Sixth births . . . . . . . . . . . . . . . . . . . . . . . . . . . 49.8 *16.3 22.5

Seventh births . . . . . . . . . . . . . . . . . . . . . . . . . 49.3 *23.8 22.0

Eighth and higher order births . . . . . . . . . . . . . 43.9 ●21.3 26.5

Mean interval (in months)

45.4 58.4

47.6 59.0

45.8 63.8

39.2 57.5

34.7 52.0

30.2 44.4

27.6 39.9

26.8 32.0

76.9 95.7 109.0

78.0 105.6 149.1

89.4 123.3 156.9

85.3 117.6 140.5

77.7 107.3 119.2

66.3 93.6 120.7

58.1 85.5 115.3

44.2 60.1 78.1

Table F. Observed mean interval since last live birth for 1970 and

1977, and adjusted mean interval since last live birth for1977, by

egeof mother: Total of reporting areas

[ Refers only to second and highar ordar live births]

1977

Age of mother 1970

Observed Adjustedl

observed

Mean interval (in months)

20-24years . . . . . . . . . . . . . 33.9 33.5 30.0

25-29years . . . . . . . . . . . . . 45.4 43.8 41.2

30-34years . . . . . . . . . . . . . 58.4 55.4 54.9

35-39years . . . . . . . . . . . . . 76.9 72.9 69.1

4044years . . . . . . . . . . . . . 95.7 93.8 82.6

45-49years . . . . . . . . . . . . . 108.0 110.9 94.5

lAd@ted bythedirect method of etendardization toreflact the 1970

birth.order distribution within each aga group; aee Technical Appendix

for a mora completa discussion of this procedura.

cent.1 Althowr htherewa sareversion to less effective

methods of contraception by blacK married women

after 1973,11 legal abortion rates rose dramatically,12

which may account for the continued lengthening m

birth interval. Among never-married black teenagers,

a dramatic increase occurred in the regular use of

contraception and in the use of oral contraceptives

from the early to mid-1970’s.1s

Despite the fact that changes in birth spacing have

been greater for black than for white mothers and

that the average interval between births is presently

longer for black mothers, a larger proportion of black

than white children are born within a very short time

after a previous live birth. In 1977, 16 percent of

black babies, compared with 11 percent of white

babies, were born less than 1% years after a previous

sibling (table B). This closer spacing of black births

can be seen for all age groups except for teenage

mothers (figure 4). The proportion of children born

less than 1 year after a previous birth was consistently

higher for black than for white mothers of all ages,

partially due to the generally higher proportion of

black premature births (gestational period of less than

37 weeks). In 1977, 37 yercent of black children

compared with 23 percent of white children born

within 1 year of a previous sibling were premature.

The mean interval since the previous Jive birth

was longer for black than for white mothers having

their second child, but for most higher order births,

the average interval was longer for white mothers.

However, as noted previously, the length of the

interval for each birth order is greatly affecttid by the

proportion of older and younger women having a

birth of that order. For all birth orders, there is a

substantially higher proportion of black than white

births to mothers less than 25 years of age, concomitant with a lower proportion of black births to older

mothers, When the interval between black births of

each order is adjusted to reflect an age distribution

that is the same for black as for white births, the

interval becomes longer for black births for all orders

(table G).

Education of mother

Items on educational attainment of parents have

been included on birth certificates in recent years to

provide a measure of the socioeconomic status of the

famjly. Data on education of the mother are generally

used to measure socioeconomic differences because

information about the father is often missing for

out-of-wedlock births. However, the number of years

of schooling is limited for young girls and is, therefore, an inadequate measure of socioeconomic status

for teenagers.

Age. –For women old enough to have had at least

a high school education, the interval between live

births generally declined as the number of years of

schooling increased. The most highly educated

mothers aged 20 years or older consistently spaced

their children the closest (table H).

The better educated population has been found

to be successful family planners and to use contraception effectively.1 A!1S Therefore, the shorter inter-
48 —

46

~mm@*m~

44

White

,&

,Mw

,,#

,0 0“

,#

##

“--a&w*# #’

42

40

38 —

/ 5

0

I 1 I I I I I

I

1970 1971 1972 1973 7974 1975 1976 1977

Year

NOTE: Rafarsonly tosacond andhigher ordar live births.

Figure 3. Meen interval since last live birth, by race: Total of reporting arees, 1970-77

birth intervals experienced by mothers with higher

levels of education are not likely to be a result of

poor family planning and excessive fertility. In 1977,

about two-thirds of the second or higher order births

to mothers who had completed college were second

births. In contrast, only about one-third of the births

to mothers with a grade school education (8 years of

school or less) were second children.

The shorter birth intervals experienced by

mothers with higher educational attainment may be

because more highly educated women are apt to

begin their families at a later age than other women.

Data in table J show that in general, as educational

attainment rises, the age at which mothers have their

first cldd increases. The median age at fust birth in

1977 was 18.4 years for mothers with only O-8years

of schooling compared with 27.5 years for college

graduates. Women who start their families later in the

reproductive years have fewer years in which to

accomplish their desired family size than do women

who begin earlier, and, therefore, they are likely to

shorten the time between births.

Race. –Although increasing educational attainment for white mothers is associated with a decline in

the interval between births, black women with higher

levels of schooling space their children further apart

than less well-educated black mothers (table H). The

mean interval between births in 1977 for white

9
Under

20 years

Black =

20-24 25-29 30-34 35-39 40-49

yaars years years years yews

Age of mother

NOTE: Rafers only to second and higher order live births.

‘igure 4. Percent of live births occurring within 18 months of the praceding live birth, by age of mothar and rata: Total of 43 reporting States and

the District of Columbia, 1977

Table G. Observad mean interval since last live birth for white births,

and observed and adjusted mean interval since last Iive birth for

black births, by live-birth order: Total of 43 reporting States and

the District of Columbia, 1977

[ Refers only to second and highar order live births]

White Black

Live-birth order

observed

Observed Adjustad7

Mean interval (in months)

Second births . . . . . . . . . . . . 42.4 46.8 54.7

Third births . . . . . . . . . . . . . 48.3 47.4 58.3

Fourth births . . . . . . . . . . . . 50.0 47.7 57.6

Fifth births . . . . . . . . . . . . . 52.2 49.4 59.4

Sixth births . . . . . . . . . . . . . 50.3 48.9 57.8

Seventh births . . . . . . . . . . . 49.1 50.4 57.5

Eighth and higher

order births . . . . . . . . . . . . 42.8 48.4 49.1

1Adju wed by *e direct mathod of standardization to eliminate

differences in the age d iasribution of black end white birtha for each

birth order; sea Technical Appendix for a more complete discussion of

this procedure.

mothers with only O-8 years of education was 46.8

months compared with 41.3 months for white

mothers who had completed college. Among black

mothers, the mean interval between births was 9

months longer for mothers with at least 16 years of

schooling than for mothers with O-8 years of education (55.2 months and 45.9 months, respectively). As

a result, in 1977, although white mothers with a

grade school education or less were spacing their

children about 1 month further apart than similarly

educated black mothers, among college graduates the

interval between black births was on the average 14

months longer than between white births.

Consistent with these findings, figure 5 illustrates

that among mothers with only a limited education a

higher proportion of black than white births occurred

within 2 years of a previous live birth. Conversely,

among mothers with more than a high school

education, relatively more white than black births

occurred within this short interbirth interval.

Differences in the ages at which black and white

mothers had their first child can only partially

explain these racial dissimilarities. Table H sh~owsthat

in 1977 black mothers of all ages with 12 years or

more of schooling consistently spaced their children

further apart than white mothers with the same

educational attainment, but that the interval since the

last birth was generally longer for white than for

10
Table H. Mean interval since last live birth, by age of mother, edwational attainment of mother, and race: Total of reporting areas, 1970 and 1977

[Refers only to second end higher order live births]

1977 1970

Age of mother and years of school

completed by mother All White Black -

All

rasesq

White

racesq

Bleck

All *S2

Allyears ofsshoo13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

8-n years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12years . ..m . . . . . . . ..m. . . . . . . . . . . . . . . . . . . . . . . . . . .

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

16yearsormore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20-24 years

Allyearsof schoo13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0-8yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9-n years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

16yearsormore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25-29 years

Allyearsofschoo13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

$?-Ilyeer s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

16yaarsormore . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . ...=...

30-34 years

Allyearsofschoo13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

S1-Ilyear s. a m. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

16yearsormore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35-39 years

Allyaarsofschoo13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

9-n years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

16yearsormore . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .

40-49 years

Allyearsofsohoo13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

9-n years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

13-15yeers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16yaarsormore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45.6

46.4

44.0

47.1

45.5

42.3

34.1

34.6

35.9

33.7

31.6

29.7

45.6

46.8

54.0

47.6

42.4

35.7

58.8

60.7

70.7

64.1

56.7

45.5

78.0

72.7

87.1

83.9

75.6

61.9

97.5

66.3

103.5

103.1

98.3

83.6

Mean interval (in months)

45.4

46.8

45.2

46.8

44.4

41.3

33.5

34.7

36.1

33.0

28.9

27.5

44.4

47.2

54.9

46.7

41.0

34.7

57.7

61.6

72.8

63.4

55.2

44.7

78.0

74.9

92.0

83.7

74.0

61.0

98.7

90.0

111.2

104.6

97.7

82.4

47.1

45.9

41.7

49.0

53.2

55.2

36.6

35.1

35.8

36.9

38.1

39.4

53.2

46.8

52.5

54.5

54.4

49.0

67.7

60.5

67.2

70.3

71.6

59.3

81.3

69.3

78.0

E

76.8

92.8

78.9

91.7

97.7

104.2

106.9

41.8

42.6

41.2

42.8

40.6

38.4

29.9

30.4

31.8

29.4

27.6

26.1

41.1

40.9

46.5

42.5

37.6

31.9

54.8

51.9

59,9

57.3

53.2

43.5

69.1

62.4

72.7

72.3

68.2

59.0

83.6

72.7

=.7

68.7

85.5

75.8

42.4

44.3

43.2

43.2

40.4

38.1

30.0

30.9

32.6

29.4

27.3

25.9

41.0

42.0.

47.7

42.4

37.2

31.7

55.2

z:

57.4

52.7

43.2

70.6

66.7

77.0

72.8

68.1

56.6

66.1

76.6

93.3

88.4

85.3

75.4

38.5

37.5

35.5

40.3

44.4

48.7

29.4

28.9

29.4

29.4

30.4

26.2

42.7

36.9

42.6

43.9

45.0

40.6

54.3

45.9

52.0

58.1

61.0

55.6

62.4

52.0

60.4

69.7

70.3

70.5

72.0

63.3

66.7

83.3

89.2

83.5

1 lnclud~s ret= otiar then whita end black.

21ncludes bir~~ to rfIotierS ieSS than 20 Yeers ‘f ‘9°.

3,ncludeS bi~S to mothers with years of sohool not ~a~.

black children born to women of comparable ages

with less thana high school education. Indeed,ifthe

age distribution of black mothers had been the same

as white mothers, then differences in the mean

intervals at higher levels of education wouldbe even

greater. For example, the observed mean interval for

black women with 13-15 years ofschooling was53.2

months compared with a mean interval of 44.4

months for white women with this level of educationalattahment. Afteradjustingthe age distribution

ofblack mothers to be comparable to white mothers,

the mean interval for black births increased to 57.6

months.

As shown in table K, the same pattern of longer

spacing between live births to better educated black

than comparably educated white mothers hold; for

11
Table J. Madian age of mother at first birth, by educational attainment of mother and race: Total of 41 reporting Statas and the

District of Columbia, 1977

Years of school

completed by mother

All White Black

races 1

Median age (in years)

Allyaars ofschoo12 . . . . . . . . . . . . . . . 22.3 22.8 19.6

0-8years . . . . . . . . . . . . . . . . . . . . . . 18.4 19.0 16.4

9-llyaars . . . . . . . . . . . . ...< . . . . . 18.2 18.3 17.8

12yaars . . . . . . . . . . . . . . . . . . . . . . 22.3 22.5 21.0

13-15years . . . . . . . . . . . . . . . . . . . . 24.0 24.2 22.8

16yearsor more . . . . . . . . . . . . . . . . . 27,5 27.5 26.8

llnclude~races other than white and black.

21n=luda~birthsto mothers with years of school notatated

each birth order. However, when age and birth order

are considered simultaneously, even among less welleducated women, the mean intervals are generally

longer for black than white mothers, but the racial

differential widens substantially asyears of schooling

increase.

A possible explanation for these racial differences

can be found in the “minority-status hypothesis,”

which purports that the greater difficulty faced by

racial minorities in attaining or maintaining social

status may result in a greater deferral or limitation of

childbirth for those minority families that are economically successful compared with nonminority

families of similar economic status.16 An additional

reason for the longer intervals between live births for

better educated black than white mothers of similar

background is that there is a higher proportion of

intervening fetal deaths among black mothers with 13

years or more of schooling. 17

Trends. –Women with comparable levels of educational attainment spaced their children further apart

in 1977 than in 1970. The increases in mean interval

between live births during this period ranged from 3

months (7 percent) among mothers with 9-11 years

of schooling to 4-5 months (10-12 percent) for

mothers with at least a high school education (table

H). These increases reflect the larger proportion of

births in 1977 than in 1970 where the average

interval was 3 years or longer (table 2). Because of

the shift in the maternal age distribution towards

younger ages between 1970 and 1977, which was

noted earlier, the increases in the mean interval for all

but the highest educational levels were actually

smaller than would have occurred if the age distribution had remained constant (table L).

For mothers in their early twenties, regardless of

educational attainment, a consistent lengthening in

40

r

o~

O-8 9-11 12 13-15 16 years

Years of school completed by mother

NOTE: Refers only to second and highar order live births.

Figura 5. Percant of live births occurring within 24 months of the preceding Iiva birth, by educational attainment of mother and race:

Total of 43 reporting States and the District of Columbia, 1977

interbirth interval of about 4 months (13-15 percent)

occurred during this period. However, among women

25 years of age or older, increases in interbirth

intervals were generally far smaller for mothers with

at least 12 years of schooling than for less welleducated women, and this trend was especially

evident among mothers in their thirties (table H).

During this period, overall fertility declinecl rapidly

among all age groups of women. However, fertility

rates for low-order births for older women did not

follow this general trend, but declined at a slower

pace or actually increased. The smaller increases in

average interval observed for better educatecl women

25 years and older maybe an indication that many of

these women, to compensate for previously deferred

births, were not postponing births to the same extent

as other women.

12
Table K. Mean interval since last live birth, by educational attainment of mother, live-birth order, age of mother, and race Total of 41 reporting

Statas and the District of Columbia, 1977

[Refers only to second and higher order live births]

Years of school completed by mother

Live-birth order and All years O-8 9-11 12 13-15 16 years

age of mother of schoolq years years years years or more

White Black White Black White Black Whita Black White Black White Black

Second births

AlIages2 . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

4049years . . . . . . . . . . . . . . . . . . . . .

Third births

All ages2 . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

4049years . . . . . . . . . . . . . . . . . . . . .

Fourth births

Alleges2 . . . . . . . . . . . . . . . . . . . . . . .

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

26-29years . . . . . . . . . . . . . . . . . . . . .

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

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

40-49years . . . . . . . . . . . . . . . . . . . . .

42.5

35.0

46.1

57.8

77.8

109.0

48.6

30.2

44.7

63.1

90.5

128.8

50.4

25.8

37.9

56.1

85.8

121.4

46.6

40.9

62.8

79.4

101.2

131.7

47.1

33.1

53.4

75.1

98.0

122.0

47.3

27.5

44.6

67.6

90.5

123.4

42.4 43.4

38.2 43.6

53.1 84.4

69.9 64.7

88.3 103.9

113.6 120.7

●

48.4

33.6

51.5

71.9

93.0

127.1

51.2

28.2

44.3

65.2

89.0

123.0

46.2

36.5

56.3

74.6

89.7

127.1

46.9

30.1

47.9

71.4

63.5

1-26.3

Maan interval (in months)

40.9

39.4

65.2

86.0

110.7

149.9

48.0

32.1

57.6

85.1

115.5

154.8

52.0

26.1

45.0

72.3

105.4

139.2

38.3

42.3

72.6

96.0

116.6

141.4

41.8

34.0

60.0

87.1

106.1

131.5

43.9

27.7

48.1

74.0

99.5

127.0

43.9

34.2

49.8

66.8

87.6

119.0

50.3

28.5

45.4

69.1

99.3

133.4

52.0

24.1

36.6

58.2

90.4

123.4

48.7

40.3

64.5

84.1

109.2

147.7

49.1

32.0

52.5

77.1

102.7

119.2

49.5

28.3

42.7

88.5

91.9

117.8

42.7

30.6

43.2

58.0

76.5

107.1

47.1

25.7

38.9

59.4

86.1

120.7

48.9

23.7

31.4

49.0

79.2

118.4

53.8

40.4

60.7

81.1

104.7

110.8

52.9

32.3

50.6

73.6

96.2

121.4

51.7

26.8

41.0

63.8

89.5

151.1

39.8

27,7

35.5

45.5

58.1

70.9

44.6

25.6

32.5

46.4

69.2

106.1

43.6

28.0

26.9

39.1

61.9

98.1

55.8

40.1

52.0

63.4

79.5

105.3

53.9

35.6

40.8

55.4

81.1

120.5

53.9

*33.3

35.4

51.6

67.1

106.3

1IncIu~eS births to mothers with yaars of school not stated.

21n~ludes births to mothars lessthen 20 Yearsof a9a.

Table L. Observed mean interval sinca last liva birth for 1970 and

1977, and adjusted maan interval since last live birth for 1977, by

educational attainment of mothec Total of reporting areas

[ Rafers only to second and highar order live births]

Years of school comdeted 1977 1970

bymother

Observed Adjustedl

observed

Mean interval (in months)

Ailyearsofschoo12 . . . . . . 45.6 46.4 41.8

0-8years . . . . . . . . . . . . . . . 46.4 49.0 142.6

9-llyaars . . . . . . . . . . . . . . 44.0 47.5 41.2

12years . . . . . . . . . . . . . . . 47.1 48.4 42.8

13-15yaars . . . . . . . . . . . . . 45.5 45.2 40.6

16yearsormore . . . . . . . . . 42.3 41.6 38.4

lAdjuwed bythadiract method of standardization toreflecttha19i’O

ega distribution within eech educational attainment group; see Tachnical Append ix fore moracomplete discussion of this procedure.

21ncluda~ births to mothers with years Of school not ~ated.

13
Intervalsincetermination of last

pregnancy

In the preceding section the discussion focused on

the interval between the current live birth and a

preceding live birth, regardless of whether there was

an intervening fetal death which occurred about 6

percent of the time. In this section, the group of

current births examined will be expanded to include

first live births where the preceding pregnancy had

terminated as a fetal death. This permits comparison

of the average interval of time the current birth

followed an immediately preceding live birth or fetal

death. In 1977, 88 percent of the preceding deliveries

for this expanded group of live births had terminated

as live births, and 12 percent as fetal deaths. The

likelihood that the previous delivery was a fetal death

was greatest for young mothers (table M).

The length of time between the termination of a

previous pregnancy and a subsequent live birth is

greatly influenced by the outcome of the preceding

pregnancy. Mothers are more likely to have a child

soon after a fetal death than after a live birth,

regardless of maternal age or parity. The average

interval since the termination of a previous pregnancy

was approximately 1Y2years longer when the previous

pregnancy ended in a live birth than when it ended in

a fetal death (table 3). In 1977, about two-thirds of

the live births following a fetal death occurred within

Table M. Percent of Iive births where the preceding pregnancy had

terminated as a fetal death, by age of mother and race: Total of 43

reporting States and the District of Columbia, 1977

[ Refers only to live births resulting from second and higher order

pregnancies]

Age of mother All White Black

races 1

Alleges . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

40-49 years . . . . . . . . . . . . . . . . . . . .

1 lncl”de~ races other than white and bleck.

11.8 11.8 12.0

19.9 21.2 17.5

13.2 13.3 12.8

10.6 10.6 10.4

9.5 9.6 9.1

9.3 9.7 8.0

8.1 8.9 5.0

2 years of the fetal death. In contrast, only slightly

more than one-fourth of the births following a live

birth were similarly spaced (table N). This implies

that for many women a fetal death represents a

reproductive failure, and it is likely that these women

are then motivated to have another birth as soon as

pqssible.

Age of mother

The interval since the termination of a previous

pregnancy lengthened with advancing matemal age

regardless of whether the previous pregnancy had

terminated as a live birth or as a fetal death (figure 6

and table 3). However, the differences by age were

not as great for births following a fetal death as for

those following a live birth. The average interbirth

interval following a live birth was almost 6 years

longer for mothers 40 years or older than for mothers

under 20 years of age (92.6 months compared with

22.8 months). For births following a fetal death, the

interval was slightly over 2 years longer for the oldest

Table N. Cumulative percent distribution of live births by interval

since termination of last pregnancy, according to outcoma of last

pregnancy: Total of 43 reporting States and the District of

Columbia, 1977

[Refers only to live births resulting from second and higher order

pregnanciasl

Interval

A II preLast Last

vious preg- pregnancy, narmy,

pregIive fetal nanciesq

birth death

O-n months . . . . . . . . . . . . . . . . . . . 4.3 3.2 14.3

12-17 months . . . . . . . . . . . . . . . . . . 17.9 14.3 48.9

18-23 tnonths . . . . . . . . . . . . . . . . . . 31.7 27.8 65.2

24-35 months . . . . . . . . . . . . . . . . . . 54.6 51.5 81.2

36-47 months . . . . . . . . . . . . . . . . . . 69.7 67.5 88.7

46-59 months . . . . . . . . . . . . . . . . . . 79.5 78.0 93.1

60months and over . . . . . . . . . . . . . . 100.0 100.0 100.0

1 ,nc,ude~ births for Vvhich the outcome of the mother’s I=* we9n-y

is unknown.

14
Last pregnancy, live birth I I

Last pregnancy, fetal death =

100

r

90

80

70

60

50

40

30

20

10

0

20 years years years years years and over

Age of mother

NOTE: Refers only to live births resulting from second end higher order pregnancies.

Figure 6. Mean interval since termination of last pregnancy, by age of mother and outcome of last pregnancy: Total of 43 reporting States end the

District of Columbia, 1977

compared with the youngest mothers (45.7 months

compared with 19.7 months).

Race

The mean interval since the termination of a

woman’s last pregnancy was about 2 months longer

for black than for white mothers whether the

previous pregnancy ended in a live birth or in a fetal

death (table 3). The average interval since the

previous delivery was consistently longer for black

than for white mothers less than 40 years of age. This

racial difference reversed only for mothers aged 40

years or more where the preceding pregnancy had

terminated as a live birth. For each maternal agebirth-order classification, the racial difference was

smaller when the current birth followed a fetal death

than when it followed a live birth.

Education of mother

The likelihood that the preceding pregnancy had

terminated as a fetal death rather than a live birth was

greater for mothers with higher levels of educational

attainment (table O). Because no distinction is made

on the birth certificate between spontaneous and

induced fetal terminations, it is not possible to

determine if this is due to a higher incidence of

previous therapeutic abortions among better educated

women.

15
Table O. Parcent of live births where the preceding pregnancy had

terminated as a fetal death, by educational attainment of mother

and race: Total of 41 raporting States and the District of

CoIumbia, 1977

[ Rafers only to live births resulting from second and higher ordar

pregnant ies]

Years of school

completed by mother

All White

races q

Black

Allyears ofschoo12 . . . . . . . . . . . . . . . 13.0 13.0 12.7

0-8 years . . . . . . . . . . . . . . . . . . . . . . 8.9 9.2 7.5

9-n years . . . . . . . . . . . . . . . . . . . . . 12.5 13.0 11.2

12years . . . . . . . . . . . . . . . . . . . . . . 12.7 12.7 12.6

13-15years . . . . . . . . . . . . . . . . . . . . 14.8 14.3 18.0

16yearsormora . . . . . . . . . . . . . . . . . 14.8 14.5 18.3

1 Includes races other than white and black.

21ncl~des births tomothers with YearS Of SChOOl nOts*ated.

NOTE: The differences in the overall percants shown in this table and

those in table M are due to the change in the composition of the

reporting araa.

As shown in table P, the proportion of current

births that occurred within 1Y2 years of the termination of a previous pregnancy generally decreased as

the mother’s years of schooling increased. When the

preceding delivery was a live birth, 16.3 percent of

the births to women with a grade school education or

less occurred within this short an interval, compared

with about one-tenth of the births to mothers who

had completed 1 year or more of college. However,

there was a greater likelihood that births following a

fetal death would be spaced less than 18 months

apart for women with a higher level of educational

attainment. The proportion of births following a fetal

death within 18 months increased from slightly over

45 percent for women with less than a high school

education to 54 percent for those who had completed

college.

Trends

On the average, in 1977 live births resulting from

second and higher order pregnancies occurred 3%

years after the termination of the preceding pregnancy. This was approximately 3 months longer than

the average time between deliveries in 1970 (table Q).

Age. –Regardless of the age of the mother, the

mean interval since the last live birth was longer in

1977 than in 1970; the average interval increased by

2-12 months (6-15 percent) (table Q). For mothers

whose last pregnancy ended in a fetal death, the mean

interval for those under 25 years of age increased 3

months (17-1 8 percent); for mothers 30 years or

older the mean interval decreased 2-3 months (4-8

percent). The proportion of births that occurred

within 1Y2 years of a previous live birth declined for

all age groups, but for births following a fetal death, a

decline was evident only for teenagers and women in

their early twenties (table 4).

Table P. Percent of live births occurring within 18 months of the

termination of the preceding pragnancy, by outcorna of last

pregnancy, educational attainment of mother, and race: Total of

41 reporting States and the District of Columbia, 1977

[Excludes births to women less than 20 years of age and the later born

in multiple deliveries. Refars only to Iiva births rasulting from

second and higher order pregnancies]

All preLast Last

Years of school vious preg- pregcompleted by mother

pregnancy, nancy,

and race live fetal nancies 1

birth death

All races2

Allyears ofschoo13 . . . . . . . . . . . . . .

@years . . . . . . . . . . . . . . . . . . . . . .

9-n years . . . . . . . . . . . . . . . . . . . . .

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

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

16yearsor more . . . . . . . . . . . . . . . .

White

Allyears ofschoo13 . . . . . . . . . . . . . .

0-8yaars . . . . . . . . . . . . . . . . . . . . . .

9-n years . . . . . . . . . . . . . . . . . . . . .

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

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

16yaars or more . . . . . . . . . . . . . . . .

81ack

Allyears ofschoo13 . . . . . . . . . . . . . .

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

9-llyaars . . . . . . . . . . . . . . . . . . . . .

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

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

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

15.4

18.5

16.6

14.7

15.7

15.0

15.0

17.8

15.4

14.4

15.6

14.9

16.9

20.1

19.4

15.8

15.4

13.8

11.2

16.3

13.5

10.7

10.6

8.9

10.5

15.5

12.0

10.1

10.4

8.7

14.1

18.6

17.1

12.9

11.2

9.2

48.2

45.3

45.2

47.1

49.0

53.9

49.3

45.4

45.4

48.1

50.6

55.3

41.2

45.0

43.7

40.8

39.5

39.5

1 [ncludes birth$ fOr which the outcoma of the mother’s last pre9mmy

is unknown.

21nc1udes races other then white and black.

slnclude~ births to mothers with yearS of school nOt stated.

Birth order. –When the current birth followed a

live birth, the average interval since the preceding -

delivery lengthened during this period for each birth

order, with increases ranging from 2 to 6 months

(3-1 7 percent) (table R). The mean interval fc)llowing

a fetal death remained virtually the same for second

order births and declined for higher order births. This

interval increased only for first live births, which was

a result of increases for mothers under 30 years of

age.

Race. –Between 1970 and 1977, the average interval since a preceding live birth increased nearly 3

times as much for black as for white births. The increase in interval was 8 months for black births (from

37.4 months in 1970 to 45.7 months in 1977) and 3

months for white births (from 41.0 months to 43.8

months) (table R). There was little change in the interval since a previous fetal death for both black and

white births. In 1977 as in 1970, this interval

averaged about 2 years for both racial groups.

16
Table Q. Mean interval since termination of last pregnancy, by outcome of last pregnancy, age of mother, and race: Total of reporting areas, 1970

and 1977

[Refers only to live births rasulting from second and higher ordar pregnancies]

All previous Last pregnancy, Last pregnancy,

Age of mother and race

pragnanciesl live birth fetal death

1977 1970 1977 1970 1977 1970

All races2

All ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

40-49 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

White

All ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

30-34 yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35-39 yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

40-49 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Black

All ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Undar 20 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

40-49 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

42.1

22.3

32.2

42.6

54.3

71.1

88.9

41.8

22.0

31.6

41.7

53.5

70.8

90.3

43.7

23.2

34.6

50.0

63.3

75.7

86.4

Mean interval (in months)

39.2 44.0 40.4

20.5 22.8 20.8

28.8 33.3 28.6

39.2 44.5 40.5

52.0 56.9 53.7

65.2 74.5 67.3

78.3 92.6 80.6

39.7 43.8 41.0

20.5 22.5 21.0

28.9 32.8 29.7

39.1 43.5 40.4

52.3 66.0 54.1

66.5 74.4 68.8

80.6 94.5 83.2

36.7 45.7 37.4

20.5 23.5 20.7

26.6 35.9 28.0

41.4 52.2 42.3

52.4 66.1 53.4

59.4 78.5 60.4

67.1 88.4 66.1

25.4

19.7

23.3

25.6

29.0

37.1

45.7

25.2

19.4

23.0

25.2

28.6

36.4

45.7

26.8

20.8

24.6

29.0

33.4

42.4

49.6

24.9

16.7

19.9

24.4

31.5

39,4

47.6

24.7

16.3

19.6

24.0

31.2

39.2

47.7

26,9

18.4

21.8

29.5

35,5

41.7

46.7

1Includes births for which the outcome of the mother’s last Pr09nancY is unknown.

21nclude~ races other than white an? black.

17
Table R. Mean interval since termination of last pregnancy, by outcome of last pregnancy, live-birth order, and race: Total of reporting areas, 1970

and 1977

[ Refers only to Iive births resulting from second and higher order pregnancies]

All previous Last pregnancy, Last pregnancy,

Live-birth order and race

pregnancies live birth fetal death

1977 1970 1977 1970 1977 1970

All races2

All birth orders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

Fifth andhigher order births... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

White

All birth orders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

Fifth and higher order births . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Black

All birth orders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

First births, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

Fifth andhigher order births . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mean interval (in months)

42.1 39.2 44.0 40.4

27.7 24.6

40.5 35.0 4;:7 35.7““”

45.3 42.8 46.6 43.7

46.3 45.2 47.7 46.2

46.8 43.5 48.0 44.2

41.8 39.7 43.8 41.0

27.5 24.4

40.0 35.1 4; ;2 35;9

45.6 43.6 47.0 44.6

46.9 46.3 48.4 47.4

47.3 44.9 48.5 45.7

43.7 36.7 45.7 37.4

29.1 26.9

44.0 34.1 4k:3 34;4

44.3 37.6 45.6 38.0

44.6 39.4 45.8 39.9

46.2 39.4 47.2 39.8

25.4

27.7

22.1

24.8

25.4

26.6

25.2

27.5

21.8

24.9

25.5

26.7

26.8

29.1

24.6

25.1

25.5

26.7

24.9

24.6

22.0

26.6

28.5

28.3

24.7

24.4

21.7

26.5

28.5

28.6

26.9

26.9

25.4

27.4

28.8

27.6

llnclude~b irthsfor which the outcome of thamother’s last pregnancy is unknown.

Zlncludes races other than white and black.

18
Low birthweight

Weight at birth has long been regarded as an

indicator of an infant’s potential for survival and

future growth. Infants of low birth weight (2,500

grams or 5% pounds or less) have a greatly elevated

risk of physical and neurological impairment 18‘z O

and are more likely to die within the first year of

life.z 1

As shown in table S, the percent of infants of low

birth weight is highest among babies born at very

short intervals after the termination of a previous

pregnancy and to a much lesser extent at very long

intervals. In 1977, 15.5 percent of the births occurring within 1 year of a previous delivery were of low

birth weight. This was 2%-3% times the percent low

birth weight among births with longer interbirth intervals. The percent low birth weight was lowest

(about 4.5 percent) when babies were born within 2-4

years after the termination of the previous pregnancy.

Live births in multiple deliveries (including first born)

have been excluded from these data to eliminate the

effect of plurality on low birth weight.

The pattern of risk of low birth weight when the

previous pregnancy terminated as a live birth is the

same as previously described, but is somewhat different when the previous pregnancy terminated as a fetal

death. For this latter group of births, the risk of low

birth weight was highest for intervals of less than 1

year (1 1.6 percent), lowest for intervals of 12-23

months (6.6 percent), and increased as the interval

increased thereafter. Additionally, births following a

fetal death within 1 year were less likely to be of low

birth weight than births following a live birth within

this short interval. For all other intervals, births

following a fetal death had a higher risk of low birth

weight. The average gestational period for fetal deaths

is considerably shorter than for live births. It is

possible that the longer gestational period associated

with a live birth is more taxing to the mother and a

more extended interval needed before the next

delivery to ensure the restoration of critical nutrients.

Births following a live birth after a relatively short

Table S. Percent of infants of low birth weight, by outcome of last

pregnancy, interval since termination of last pregnancy, and race:

Total of 43 reporting States and the District of Columbia, 1977

[Refers only to live births resulting from second and higher order

pregnancies. Excludes plural births]

Ail preLast Last.

vious preg- pregInterval and race

pregnency, nancy,

live fetal nancies 1

birth death

All races2

All intervals . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . .

12-23 months . . . . . . . . . . . . . . . . . .

24-35 months . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . .

48months And over . . . . . . . . . . . . . .

White

All intervals . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . .

12-23 months . . . . . . . . . . . . . . . . . .

24-35 months . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . .

48months And over . . . . . . . . . . . . . .

Black

All intervals . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . .

12-23 months . . . . . . . . . . . . . . . . . .

24-35 months . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . .

48 months And over . . . . . . . . . . . . . .

5.8

15.5

6.0

4.5

4.4

5.2

4.7

12.7

4.8

3.6

3.6

4.3

11.3

25.8

12.1

9.9

9.1

9.3

5.2

19.2

5.9

4.2

4.2

5.0

4.2

16.0

4.6

3.4

3.4

4.2

10.5

27.7

11.9

9.6

8.8

9.1

8.3

11.6

6.6

7.8

8.2

8.8

7.0

10.0

5.6

6.7

7.2

7.6

14.7

21.8

13.1

13.0

13.2

14.9

1 ,ncludes births for which the outcome of the mother’s last pre9nancy

is unknown.

Zlncludes races other then white end black.

time are therefore more likely to have an unfavorable

outcome than births closely following a fetal death.

Data which suggest that short-birth intervals are

related to low birth weight and high levels of fetal

and infant mortality are confounded. by the fact that

these adverse outcomes are associated with shortened

periods of gestation which in turn shorten the birth

interval. However, when only full-term births are

19
considered, the pattern of an increased risk of low

birth weight for the shortest intervals is still evident

(table T). Similarly, variations in the risk of low birth

weight for different interbirth intervals do not merely

reflect maternal age differences, which also have a

profound effect on birth weight. The same pattern of

a higher incidence of low birth weight for very short

and very long intervals and an optimum interval of

between 2 and 4 years is evident for all maternal ages

(table U).

Additionally, the low birth weight associated with

short interbirth intervals cannot be solely attributed

to socioeconomic differences. As shown in figure 7,

regardless of mother’s educational attainment, the

risk of low birth weight is highest when the birth

interval is less than 1 year. Among births to mothers

with the most schooling, the percent of low birth

weight was 3-5 times higher among those born at

intervals of less than 1 year following a live birth than

among those born at longer intervals. The far higher

level of low birth weight among births following a live

birth within 1 year than among births following a

fetal death within this period as noted previously is

also evident for all levels of educational attainment

(see also table 5).

The associations between low birth weight and

interbirth intervals according to the factors discussed

are similar for white and black births, but the levels

of low birth weight are consistently higher for black

births.

Table T. Percent of full-term infants of low birth weight, by outcome

of last pregnancy, interval since termination of last pregnancy, and

race: Total of 41 reporting States and the District of Columbia,

1977

[ Refers only to live births of 37 weeks’ gestation or more resulting from

sacond and higher order pregnancies. Excludes plural births]

Last Last

Interval and race pregnancy, pregnancy,

live birth fe,ta/ death

White

All intervals . . . . . . . . . . . . . . . . . . . . . . . 2.0 2.9

I-n months . . . . . . . . . . . . . . . . . . . . . . 4.5 3.5

12-23 months . . . . . . . . . . . . . . . . . . . . . 2.0 2.6

24-35 months . . . . . . . . . . . . . . . . . . . . . 1.7 3.0

36-47 months . . . . . . . . . . . . . . . . . . . . . 1.8 3.5

48 months and over . . . . . . . . . . . . . . . . 2.2 3.4

Black

Ali intervals . . . . . . . . . . . . . . . . . . . . . . . 4.9 5.9

I-n months . . . . . . . . . . . . . . . . . . . . . . 10.1 6.6

12-23 months . . . . . . . . . . . . . . . . . . . . . 5.5 5.6

24-35 months . . . . . . . . . . . . . . . . . . . . . 4.8 5.9

36-47 months . . . . . . . . . . . . . . . . . . . . . 4.4 6.3

48months andover . . . . . . . . . . . . . . . . 4.6 5.9

A study of the effect of the close spalcing of

births7 concluded that sufficient time between births

is needed for optimum fetal body and brain development. The depression in birth weight seen in closely

spaced births may be attributed to intrauterine

impoverishment because of insufficient time between .

pregnancies to restore supplies of critical nutrients.

20
Table U. Percent of infants of low birth weight, by age of mother, interval since last live birth, and race: Total of 43 reporting States and the District

of Columbia, 1977

[Refers only to second and higher order live births. Excludes plural births]

Age of mother

Interval and race All Under

20

20-24 25-29 30-34 3539 40-49

ages

years

years years years years years

All racesl

Allintewals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-23 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3647 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . .

White

Allintervais . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-23 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3647 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-58 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . .

Black

Allintervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48.59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60 monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . .

5.5

19.6

6.1

4.4

4.5

4.7

5.8

4.4

16.3

4.8

3.6

3.6

3.9

4.8

10.9

28.1

12.1

9.9

9.4

9.1

9.9

10.6

27.0

10.2

8.2

8.3

9.8

9.9

7.9

23.2

7.7

5.9

5.2

5.0

7.4

15.5

33.7

15.2

12.7

12.9

14.2

12.3

6.1

19.3

6.2

4.9

5.4

5.7

6.8

4.8

16.1

5.0

4.0

4.3

4.6

5.0

11.2

27.8

11.9

9.8

9.8

9.6

11,0

4.5

15.3

4.7

3.5

3.7

4.1

5.4

3.7

12.6

3.9

2.9

3.2

3.5

4.4

9.4

23.7

9.7

8.8

8.2

8.o

9.3

4.6

14.4

4.5

3.8

3.5

3.9

5.3

4.0

12.7

3.8

3.3

3.1

3.4

4.6

‘8.0

19.7

9.7

8.5

7.7

8.5

8.8

6.3

14.3

6.0

4.7

4.8

5.9

6.7

5.3

13.5

4.9

4.1

4.3

5.2

5.7

10.8

16.2

10.4

8.3

8.2

9.8

11.4

7.6

15.3

6.1

4.3

5.5

5.8

8.6

6.5

13.7

4.6

3.1

5.3

5.0

7.5

12.2

11.1

11.5

9.0

8.3

8.1

13.5

1,nclude~ race5 other than white and black.

21
Last pregnancy, }ive birth

25

20

s

815’

&

0.

10

5

0

20

15

\ ‘\*.

I 1 I I I I

I

Last pregnancy, fetal death

:\ L—————

+

‘++ \

------ ------ -- =--- .

\ ->:-=m-~:”.: #,

*

\ ~—————————

9-11 years

0% years

12 years

13-15 yearn

16 years or more

0.8 yaars

9-11 years

12 yaars

13-15 yeerg

76 yaars or mora

I I I I I I

I

1-11 12-17 18-23 24-35 36-47 46-59 60 months

months months months months months months and over

Interval sincetermination of last pregnancy

NOTE: Refers OnlY to live births resulting from second and higher ordar pregnancies. Excludes plurel births.

Figure 7. Percent of infants of low birth weight, by interval since termination of last Iiva birth and last fetal death and educational attainment of

mother: Total of 41 reporting States and the District of Columbia, 1977

22
References

1Westoff, C. F.: Trends in contraceptive practice: 1965-1973.

Fare. Plann. Perspect. 8(2): 54-57, Mar. /Apr. 1976.

2Forrest, J. D., Sullivan, E., and Tietze, C.: Abortion in the

United States, 1977-1978. Fare. Pkmn. Perspect. 11(6):

329-341, Nov./Dee. 1979.

3National Center for Health Statistics: Contraceptive utilization among currently married women 15-44 years of age:

United States, 1973, by K. Ford. Monthly Vital Statistics

Report. Vol. 25, No. 7, Supp- DHEW Pub. No. (HRA)

76-1120. Health Resources Administration. Rockville, Md.,

Oct. 4, 1976.

4Bumpass, L. L., Rindfuss, R. R., and Janosik, R. B.: Age and

marital status at first birth and the pace of subsequent

fertility. Demography 15(1): 75-86, Feb. 1978.

5Trussell, J., and Menken, J.: Early childbearing and subsequent fertility. Fan-z Plann. Perspect. 10(4): 209-218, July/

Aug. 1978.

6Freedman, R., and Coombs, L.: Childspacing and family

economic position. Amer. Sociol. Rev. 3 1(5): 631-648, Oct.

1966.

7Honey, W. L., Rosenbaum, A. L., and Churchill, J. A.: Effect

of rapid succession of pregnancy, in Perinatal Factors Affecting Human Development. Scientific Publication No. 185.

Washington, D.C. Pan American Health Organization. Oct.

1969. pp. 41-44.

‘Henry, L.: French statistical research in natural fertility, in

M. C. Sheps and J. C. Ridley, eds., Public Hea@h and

Population Change– Current Research Issues. Pittsburgh. University of Pittsburgh Press, 1965. pp. 333-350.

‘Potter, R. G., Jr.: Birth intervals: Structure and change.

Pop?.d. Stud. 17:, 155-166, 1963.

10Grabill, W. H., and Davidson, M.: Recent trends in

childspacing among American women. Demography 5(1):

212-225, 1968.

11National Center for Health Statistics: Contraceptive utilization in the United States: 1973 and 1976, by K. Ford.

Advance Data from Vital and Health Statistics, No. 36. DHEW

Pub. No. (PHS) 78-1250. Public Health Service. Hyattsville,

Md. Aug. 18, 1978.

12Tietze, C: Induced abortion: 1977 supplement. Reports on

Population/Family Planning, No. 14, Supp. The Population

Council, Inc. New York, N.Y. Dec. 1977.

13 Zelnick, M., and Kantner, J. F.: Sexual and contraceptive

experience of young unmarried women in the United States,

l_976 and 1971. Ffzm. Plann.-Perspect. 9(2): 55-71, MsI./ApI.

1977.

14 National Center for Health Statistics: Patterns of ag~egate

and individual changes in contraceptive practice, United States,

1965-1975, by C. F. Westoff and E. F. Jones. Vital and Health

Statistics. Series 3-No. 17. DHEW Pub. No. (PHS) 79-1401.

Public Health Service. Washington. U.S. Government Printing

Office, June 1979.

15Whelpton, P. K., Campbell, A. A., and Patterson, J. E.:

Fertility and Family Planning in the United States. Princeton,

N.J. Princeton University Press, 1966. pp. 246.

16Goldscheider, C., and Uhlenberg, P.: Minority group status

and fertility. Amer. J. Sociol. 74:361-372, Jan. 1974.

17National Center for Health Statistics: Unpublished tabulation.

18Harper, P. & and Wiener, G.: Sequelae of low birth weight.

Ann. Rev. Med. 16:405-420, 1965.

19 Lubchenco, L. O., et. al.: Sequelae of premature birth. Am.

J. Dis. Child. 106:135-149, July 1963.

20 National Center for Health Statistics: Congenital anomalies

and birth injuries among live births: United States, 1973-74,

by S. Taffel. Vital and Health Statistics. Series 21-No. 31.

DHEW Pub. No. (PHS) 79-1909. Public Health Service.

Was@ngton. U.S. Government Printing Office, Nov. 1978.

21 National Center for Health Statistics: A study of inf at

mortality from linked records by birth weight, period of

gestation, and other variables, United States, by R. J.

Armstrong. Vital and Health Statistics. Series 20-No. 12.

DHEW Pub. No. (HSM) 72-1055. Health Services and Mental

Health Administration. Washington. U.S. Government Printing

Office, May 1972.

23
_Listof Deta”iledTables

1. Mean interval since last live birth, by live-birth order, age of

metier, and race: Total of reporting areas, 1970-77. . . . . .

2. Percent distribution of live births by intewal since last live

birth, according to educational attainment of mother, agaof

mother, and race: Total of reporting areas, 1970 and 1977 . .

3. Mean intawal since termination of last pregnancy by outcome Of kt pragnancy, aga of mothar, Iiva+jrth order, and

race: Total of 43 reporting States and the District of Columbia,1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. Parcant distribution of live births by intawal since termina25 tion of last pragnancy, according to outcome of last pragnancy, age of mother, and race: Total of reporting areas,

1970and 1977 . . . . . . . . . . . . . . . . . . . . . . . . ...35

29 5. Percent of infants of low birth weight, by educational attainment of mother, outcoma of last pregnancy, intewall sinca

termination of Iastpragnancy, and rata: Total of 41 reporting States andthe District of Columbia, 1977 . . . . . . . . . 40

34

24
Tablel. Mean intewal since last live birth, bylive-titih ordar, weofmother, and race: Total ofraporting areas, 1970-77

[Refers only to second and higher order live births]

Live-birth order, age of mo ther, and race 1977 1976 1975 1974 1973 1972 1971 1970

All racasq

All second and higher order births

All ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

25-28 yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Second births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

4549years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - . . . . . . -- . . .

Third births

AH ages . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fourth births

All ages . . . . . . . . . . . . . . -. . . . . . . . . . . . . . . . . . . .- . . . . . . . .

Undar20years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

45-49 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fifth births

Alleges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

25-29yeers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

45-49 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sixth births

All ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Under20years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1includes ~acesothar than white and black.

45.5

23.2

33.9

45.4

58.4

76.9

95.7

109.0

43.0

23.6

35.7

47.6

59.0

78.0

105.6

149.1

48.1

20.7

30.8

45.8

63.8

89.4

123.3

156.9

49.3

18.8

26.4

39.2

57.5

65.3

117.6

140.5

51.3

18.5

24.0

34.7

52.0

77.7

107.3

119.2

49.8

●16.3

22.5

30.2

44.4

66.3

93.6

120.7

45.1

22.9

33.7

45.3

58.5

76.7

92.9

108.6

42.3

23.3

35.4

47.1

58.8

77.7

102.2

131.2

47.8

20.7

30.8

45.9

84.1

90.2

121.7

147.7

49.8

19.1

26.7

40.1

58.8

86.3

115.3

141.4

52.1

20.0

24.3

35.8

53.5

78.1

105.7

141.3

51.2

*1 8.8

22.1

31.3

46.5

67.9

96.3

120.6

Mean interval {in months) .

44.6

22.7

33.3

44.6

58.1

76.1

92.0

101.9

41.2

23.0

34.8

46.1

57.7

77.5

107.9

135.4

47.4

20.6

30.7

45.5

64.2

90.5

121.6

146.9

50.1

19.0

26.8

40.2

59.1

85.9

115.2

128.9

52.5

20.1

24.6

36.1

64.0

78.1

102.9

125.2

51.4

●15.1

23.0

32.2

46.4

68.0

91.4

117.7

43.9

22.5

32.8

43.7-

57.5

74.9

88.2

104.5

40.2

22.7

34.1

44.9

57.0

77.8

98.4

138.8

47.0

20.9

30.5

45.2

63.6

89.8

119.4

‘147.8

50.1

19.6

27.3

40.2

59.2

85.2

111.1

141.1

51.9

18.9

24.5

36.1

54.0

77.1

102.7

122.5

50.9

*24.6

23.6

31.5

47.4

67.4

87.2

121.6

43.3

21.9

31.8

42.7

57.0

73.7

86.6

101.5

39.2

22.2

33.1

43.7

57.0

79.2

102.2

132.5

46.5

20.2

29.9

44.7

63.7

90.0

115.5

157.5

49.6

19.7

26.8

39.7

59.1

64.2

108.9

123.3

51.2

21.1

24.8

35.8

53.4

75.0

100.2

125.1

49.8

*1 6.4

22.5

31.7

47.3

65.6

83.8

111.8

42.6

21.2

30.8

42.0

56.5

72.3

85.6

101.4

38.1

21.5

32.0

43.0

57.7

81.2

104.0

133.7

45.9

19.8

29.2

44.6

64.0

89.9

119.7

138.5

48.5

18.3

26.1

39.2

58.6

82.8

110.7

138.6

49.8

18.3

23.5

35.4

52.8

74.3

93.6

127.5

48.6

25.4

22.6

31.1

46.5

64.1

84.5

107.8

41.8

20.7

30.1

41.5

!55.7

69.9

82.8

97.2

37.0

20.9

31.3

42.5

57.9

80.0

104.1

121.4

44.9

19.5

28.8

44.2

63.4

89.2

115.1

140.1

47.7

18.7

26.0

39.5

57.9

80.3

106.8

124.6

48.6

19.1

23.6

35.5

52.4

71.9

92.5

125.0

47.1

*1 9.4

21.9

31.4

46.1

61.6

80.8

107.5

41.8

21.1

30.0

41.2

54.9

69.1

82.6

94.5

36.7

21.3

31.0

42.0

57.8

79.9

104.3

132.0

45.0

19.9

29.0

43.9

62.8

89.3

117.4

141.8

47.7

19.5

26.3

39.6

57.4

79.5

105.2

125.4

48.4

20.0

24.8

36.0

51.4

70.5

91.1

109.3

46.2

22.7

22.7

31.7

44.8

60.3

80.0

103.2

25
Table 1. Mean interval since last live birth, bylive-birth order, age of mother, and race: Total of reporting areas, 1970-77 –Con.

[Refers only to second and higher order live births]

Live-birth order, age of mo ther, and race 1977 1976 1975 1974 1973 1972 1971 1970

Ail races–Con. 1

Seventh births

All ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

45-49 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Eighth and higher order births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

White

All birth orders

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Second births

Ail ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Third births

Al lege s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fourth births

Ail ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

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

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

Ilncludes reces other than white and black.

49.3

*23.8

22.0

27.6

39.9

58.1

85.5

115.3

43.9

*2 I .3

26.5

26.8

32.0

44.2

60.1

78.1

45.2

22.8

33.4

44.4

57.4

76.7

97.4

112.3

42.4

23.1

34.8

46.1

57.5

76.2

104.3

137.0

48.3

20.3

30.1

44.8

62.9

89.6

125.6

166.6

50.0

19.0

25.8

37.9

56.0

85.0

118.8

138.9

49.3

‘20.0

22.1

27.7

41.3

59.0

82.1

103.0

44.3

‘23.0

26.7

26.4

33.0

45.3

58.5

80.9

}

45.1

22.6

33.3

44.4

57.7

76.7

94.7

111.7

41.9

22.9

34.6

45.9

57.3

75.7

100.9

139.4

48.3

20.2

30.2

45.0

63.5

90.3

123.0

153.2

50.7

19.1

26.1

38.9

57.7

86.1

116.2

140.2

Mean intewal (in months)

49.7

*1 8.3

22.3

29.6

41.5

59.3

82.5

92.7

44.5

“32.8

29.2

26.3

34.4

45.5

57.9

75.7

44.6

22.4

32.9

43.9

57.5

76.6

93.4

104.3

41.0

22.7

34.2

45.1

56,5

76.7

105.4

140.4

48.0

20.2

30.2

44,7

63.8

91.1

122.4

155.4

51.1

18.9

26.2

39.2

58.1

86.2

115,9

130.3

49.1

‘20.5

23.2

28.9

41.0

60.5

79.0

93.5

43.4

*22.2

28.5

27.1

34.4

44.4

55.8

75.7

44.0

22.1

32.5

43.2

57.0

75.5

90.4

106.8

40.0

22.3

33.6

44.0

55.8

76.4

98.2

137.8

47.7

20.7

30.0

44.6

63.2

90.4

121.1

151.3

51.1

19.7

26.8

39.3

58.5

85.3

111.8

145.2

48.4

*20.6

21.8

29.2

41.4

59.7

76.0

97.4

42.6

*26.6

26.7

26.0

33.4

43.9

55.8

72.3

43.6

21.7

31.7

42.3

56.7

74.6

88.1

105.5

39.2

21.9

32.8

42.9

55.9

77.7

98.1

123.2

47.3

19.9

29.6

44.2

63.4

90.8

115.7

160.9

50.7

20.6

26.4

39.1

58.5

84.3

111.0

129.0

47.0

*22.4

22.1

28.8

41.0

56.7

75.4

99.7

41.3

*23.8

29.1

25.7

33.5

42.7

53.4

71.4

43.0

21.2

30.7

41.7

56.5

73.4

87.5

104.9

38.1

21.4

31.7

42.3

56.7

79.5

102.0

133.3

46.7

19.6

29.0

44.2

63.7

91.2

120.7

140.6

49.6

19.0

25.8

38.5

58.2

83.1

111.5

139.5

45.2

‘20.7

22.1

28.4

40.9

55.0

70.9

87.2

39.9

*13.O

29.5

26.0

33.4

41.7

51.’1

66.4

42.;2

20.G

3G.’I

41.:3

55.9

71.:2

85.”1

101.1

37.’1

20.!3

31.’1

4113

56.!3

79.0

100.”7

130.0

45.7

19.’1

28.7

44.0

63.4

89.7

117.4

141.3

48.”7

18.:3

25.13

39.’1

57.!5

80.!5

107.”7

128.!3

43.8

*55.3

24.3

28.3

39.7

53.4

66.8

92.4

39.0

*2 I .3

27.6

26.1

32.9

40.7

50.9

61.1

42.3

21.2

30.1

41.1

55.2

70.4

84.8

98.4

36.9

21.3

30.9

41.4

57,0

79.3

104.0

144.5

45.9

19.7

29.1

43.7

62.7

89.8

118.5

148.8

48.9

22.3

26.4

39.4

67.2

79.8

106.4

127.8

26
Tablel. Mean interval since lamlive birth, bylive-birth Order, age of mother, and race: TOtalOf reporting areas, 1970-77–Con.

[ Refars only to second and highar order live births]

Live-birth order, age of mother, and race 1977 1976 1975 1974 1973 1972 1971 1970

White–Con.

Fifth births

All ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

25-29yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,

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

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

40-44yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45-49yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sixth births

All agas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Under20yaars . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Seventh births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

40-44yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Eighth and higher ordar births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

25-29yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Black

AH birth orders

All ages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Undar 20 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

45-49 yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Second births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .

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

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

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

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

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

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

4549years, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

52.2

20.3

23.6

33.4

50.2

76.6

108.1

122.3

50.3

* 18.4

22.1

29.3

42.6

64.3

92.4

122.3

49.1

*24.5

25.0

26.6

37.5

55.4

85.5

113.4

42.8

*21 ,3

26.1

28.5

30.0

41.9

58.0

75.5

47.3

23.9

36.6

53.4

68.0

81.6

92.4

102.8

48.8

24.7

40.8

62,7

79.0

98.6

127.3

*2I 4.4

53.1

21.7

23.8

34.8

52.0

77.1

105.5

146.3

51.9

*15.3

22.3

30.3

44.5

66.6

95.5

117.0

49.2

26.0

26.9

38.7

57.6

80.8

100.2

43.5

‘23.0

30.4

26.8

31.6

42.8

57.4

80.8

46.2

23.6

35.9

52.4

67.2

80.1

88.7

105.3

45.0

24.2

39.8

60.7

79.3

101.8

121.0

Mean interval (in months)

53.6

21.9

23.9

35.1

52.7

77.5

103.0

121.1

52.0

*19.3

23.9

31.5

44.4

67.0

92.0

115.7

49.6

24.7

28.8

39.9

57.1

81.1

93.2

44.2

‘27.6

30.4

26.3

32.9

43.9

57.0

76.4

45.1

23.3

35.4

51.2

65.7

77.6

88.2

96.4

43.2

23.8

39.0

59.2

76.9

97.3

131.9

126.4 *113.1

53.3

*23.8

24.2

35.2

53.2

77.1

103.4

126.6

51.7

*14.O

23.2

30.8

45.7

66.3

87.9

119.0

49.4

*24.O

22.5

28.1

38.7

58.9

78.1

91.9

43.2

*23.7

33.1

27.9

33.7

42.8

55.4

75.3

43.7

23.1

34.3

49.5

63.8

75.0

81.1

97.7

41.5

23.6

37.5

57.4

76.0

97.7

109.3

52.6

28.0

24.6

35.4

52.6

74.6

102.3

129.3

51.0

● 14.4

22.9

30.9

45.9

65.5

83.8

118.0

49.1

*29.O

24.1

28.3

40.0

58.9

74.8

98.o

42.9

●28.3

28.8

26.4

32.6

42.8

55.5

73.6

42.4

22.3

32.8

47.8

61.9

72.0

81.0

86.9

39.8

22.8

35.9

56.2

77.0

102.6

138.8

*138.7 ●208.1

51.2

19.5

23.5

34.8

52.2

74.2

94.2

123.7

49.8

*1 4.0

23.1

30.4

45.6

63.7

84.7

107.9

47.8

●35.5

22.8

28.1

39.9

55.5

74.3

103.0

42.0

‘27.0

24.7

26.0

33.1

42.3

53.5

72.7

41.0

21.4

31.4

46.2

59.4

68.8

78.0

87.9

38.4

21.9

34.5

55.5

76.4

107.2

123.7

* 126.0

49.9

19.1

23.5

35.1

52.0

71.7

93.4

128.6

48.3

* 29.0

22.6

30.8

45.5

61.2

80.6

106.6

45.7

22.2

27.7

39.8

54.1

69.5

86.1

40.6

*1 2.0

35.4

26.9

32.7

41.7

51.4

66.6

39.8

21.0

30.3

44.3

57.1

65.5

73.4

80.3

36.8

21.3

,33.1

54.0

75.9

101.7

136.7

*60.6

49.7

24.4

25.4

35.8

51.2

70.4

91.4

105.9

47.4

‘33.0

23.5

31.5

44.3

59.9

80.1

106.6

44.8

*47.O

25.2

28.5

39.1

52.5

66.6

92.7

39.9

‘20.0

34.1

26.7

32.8

40.7

50.6

61.3

38.9

21.0

29.6

43.2

55.2

63.3

71.9

75.4

35.8

21.4

32.1

53.2

74.0

92.4

124.2

● 57.3

1

27
Table 1. Mean interval since last live birth, bylive-Mflh order, age of mother, and race: Total ofreporting areas, 1970-77 –Con.

[ Refers only to second and highar order live births]

Live-birth order, age of mother, and race 1977 1976 1975 1974 1973 1972 1971 1970

Black–Con.

Third births

Alleges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Under20yeers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mean interval (in months)

47.4

21.2

33.1

53.5

75.0

98.2

119.7

●96.4

46.4

21.4

32.9

53.4

74.0

97.5

123.1

132.2

47.4

19.1

27.7

45.8

68.1

91.2

112.0

141.8

49.7

18.4

25.2

39.0

61.3

85.4

108,2

114.5

50.2

*19.9

22.0

33.4

53.9

74.9

100.9

136.1

49.9

* 20.0

19.8

28.6

47.9

65.3

88.4

110.0

46.3

23.0

26.1

35.6

50.7

61.9

84.1

45.5

21.1

32.7

52.6

73.8

96.0

128.3

‘112.5

44.0

21.2

32.1

51.3

72.8

95.2

118.1

* 154.8

43.0

.20.6

31.2

50.8

73.1

93.5

125.3

*150.7

44.9

19.0

27.6

43.7

66.0

87.2

108.4

*99.4

46.4

18.4

25.2

37.9

58.9

79.5

88.9

*94.9

46.8

*1 7.2

22.0

33.8

53.1

67.9

84.3

* 78.5

47.2

*1 5.0

20.4

30.8

45.4

63.8

83.7

98.4

42.6

*13.O

24.1

25.8

35.1

46.9

57.2

70.0

41.6

20.0

30.2

50.2

72.5

88.5

123.1

‘144.1

43.6

17.9

26.9

43.3

64.2

64.4

110.3

“166.6

44.8

17.4

23.6

37.8

57.3

78.2

92.2

144.2

45.4

*28.1

22.1

32.9

51.0

67.2

86.8

*117.O

45.6

●12.0

21.8

29.7

44.8

62.4

82.1

83.5

40.1

*20.O

25.5

25.0

34.2

43.9

53.7

68.8

40.3

20.()

29.4

47.8

68.8

92.4

105.4

131.2

42.7

18.9

26.4

42+)

63.8

81.41

108.$)

*99.1

43.5

18.9

23.9

37.3

55.$)

75.6

88.11

97.C)

43.5

*1 2.3

21 cJ

32.ir

49.3

65../i

83.3

‘1 05.(1

44.11

*20.7

22.2!

29.3

44.7

59.:?

78.3

94.11

39.()

●14.:)

23.7

25.2!

35.1

42.6

50.8

66.7

39.8

20.0

29.0

47.4

70.2

92.2

112.9

106.6

41.7

17.8

26.0

41.8

61.9

82.4

97.9

*82.7

42.8

16.6

24.0

37.1

54.3

72.0

92.0

131.3

42.4

17.9

22.2

32.4

48.2

64.5

79.8

71.9

41.3

‘58.0

24.1

28.3

42.3

58.2

68.2

92,2

38.0

* 25.0

22.3

25.5

33.3

41.2

52.1

83.4

Fourth births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

30-34yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

46.3

19.6

28.3

44.9

66.6

89.1

114.3

*I 29.4

47.7

18.7

27.5

44.5

67.8

90.9

121.1

*159.4

47.1

19.2

27.9

45.2

68.7

90.1

116.6

126.1

Fifth births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

25-29yeara . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

45-49years ...,........,.. . . . . . . . . . . . . . . . . . . . . . . . . . .

49.4

17.2

24.5

38.0

60.6

85.3

107.4

*111.8

49.5

19.2

25.3

39.2

61.4

84.8

107.0

‘146.2

47.8

17.1

25.1

39.3

59.7

79.6

103.1

*101.6

Sixth births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Under20years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

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

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48.9

+’14.9

22.4

32.2

50.6

74.1

100.9

*140.6

50.0

*1 3.8

22.3

33.8

48.9

“27.6

24.1

33.2

54.3

73.9

85.7

*I 26.4

53.6

73.3

90.9

130.6

Seventh births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Under20yaers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

4044yaers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45-49years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

50.4

*23.O

20.6

28.8

46.6

68.1

87.1

●118.9

50.4

*18.3

20.8

31.4

46.2

66.7

90.1

*90.9

48.8

●19.3

23.7

30.3

47.2

66.4

81.6

* 102.4

Eighth and higher order births

All eges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Under20yeers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

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

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

40-44yeara . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .

45-49vears . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

46.4

27.7

25.2

35.0

49.2

66.0

86.8

45.7

*38.8

29.2

26.5

36.8

49.4

60.8

77.6

44.3

“20.0

23.5

26.6

36.2

48.3

58.0

79.8

28
Table 2. Percent distribution of live births by interval since last live birth, according coeducational attainment ofmother, a9eof mother, andrac=

Total of reporting areas, 1970 and 1977

[ Refers only to second and higher order Iiva births]

1977 7970

Age of mother,

Years of school completed by mother Years of school compleied by mother

interval, and race

All O-8 9-11 12 13-15 16 years

All

years of

O-8 9-11 12

years of

13-15 16 years

yaars’

schoolq

yaars years yaars or mora

schoolq

years yaars years years or mora

Al I races2

Al I ages

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

3647 months . . . . . . . . . . .

48-71 months . . . . . . . . . . .

72 months and over . . . . . . .

Under 20 years

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

3647 months . . . . . . . . . . .

46-71 months . . . . . . . . . . .

72 months and over . . . . . . .

2024 years

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

3647 months . . . . . . . . . . .

48-71 months . . . . . . . . . . .

72 months and over . . . . . . .

25-29 years

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

3647 months . . . . . . . . . . .

46-71 months . . . . . . . . . . .

72 months and over . . . . . . .

30-34 years

All intervals . . . . . . . . . . . . .

10 months (plural births) . . . .

1-11 months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

3647months . . . . . . . . . . .

4&71 months . . . . . . . . . . .

72 months and over . . . . . . .

See footnotes et end of table.

100.0 100.0 100.0 100.0 100.0

2.2

28.9

28.3

16.8

14.5

9.2

100.0

7.4

37.0

25.9

14.8

14.8

100.0

5.9

49.1

27.3

10.5

5.9

1.3

100.0

2.3

33.4

33.7

17.4

10.4

2.9

100.0

1.5

21.3

24.3

18.4

21.5

13.0

100.0

1.4

1.6

23.0

23.1

16.3

18.4

16.3

100.0

2.5

6.0

!52.4

26,9

9.2

2.8

0.1

100.0

1.4

2.1

30.0

28.1

18.3

16.5

3.6

100.0

1.2

1.0

18.9

23.4

17.7

21.6

16.2

100.0

;;

14.1

17.3

14.8

21.2

30.8

100.0

1.1

3.1

27.9

19.7

12.9

16.7

18.6

100.0 100.0 100.0

1.3 1.5

!2:; 1.3 0.9

28.0 21.0 21.6

21.3 22.6 24.4

14.2 16.7 17.0

16.9 19.6 18.6

15.7 17.5 16.1

100.0

1.6

0.6 }

21.3

28.5

19.2

16.8

11.9

100.0

3.3

28.4

23.5

15.4

16.2

13.2

4.2

31.8

20.9

12.6

15.2

15.1

4.2 2.9 2.6

31.5 26.3 27.7

21.7 23.5 25.7

13.8 16.2 16.5

15.4 17.3 15.9

13.5 13.8 11.6

100.0

1.5

6.6

50.8

25.9

10.7

4.3

0.2

100.0 100.0

2.2 3.7

6.0 5.8

53.7 50.8

27.3 26.5

8.5 9.7

2.1 3.4

0.1 0.1

100.0

6.8

3.7

37.4

27.8

16.3

7.3

0.7

100.0 100.0

10.8

59.8

22.3

5.5

1.3

0.3

100.0 100.0 100.0 100.0

●8.3-1 9.9 10.4 12.7 15.1

*4 I .7

“25.0

●25.O

57.6

22.9

60.4 60.1 52.1

22.8 19.7 23.5

5.0 5.4 7.0

1.1 1.5 2.0

0.3 0.6 0.3

7.2

2.0

0.3

100.0

1.0

2.3

28.0

25.4

18.9

19.6

4.8

100.0

1.4

2!!::

28.9

19.1

15.7

2.8

100.0

2.2

1.9

36.0

29.4

15.5

12.1

3.0

100.0 100.0

4.3

37.7

29.4

16.5

10.4

1.7

100.0 100.0 100.0 100.0 100.0

1.0

3.6

4.3

2.3 }

43.0

26.1

10.8

10.0

3.5

5.3

40.0

25.6

14.0

12.0

3.1

4.1 4.2 4.3

34.9 37.5 42.5

27.3 30.8 31.3

17.5 16.9 14.6

13.6 9.5 6.4

2.6 1.2 1.0

32.2

24.0

15.9

17.8

5.4

100.0

1.0

1.4

16.9

15.4

13.2

24.2

27.8

100.0

1.1

0.9

16.4

21.1

18.0

24.4

18.0

100.0

1.2

0.7

20.0

26.7

19.2

20.1

12.1

100.0

1.9

0.7 }

25.5

34.4

19.4

12.4

5.7

100.0

2.2

23.9

24.1

18.0

20.6

11.1

100.0 100.0 100.0 100.0 100.0

0.9

2.5 3.4

28.7

21.0

15.0

18.9

13.0

2.5 2.0 2.1

22.0 21.4 25.4

18.8 23.0 27.8

15.3 18.9 19.8

23.2 23.1 18.1

18.1 11.6 6.8

23.3

18.4

13.9

21.5

19.4

100.0 100.0 100:0 100.0

1.0

1.6

18.8

14.8

10.6

18.5

34.6

100.0 100.0

1.3

1.2 k;

13.6 12.4

11.9 14.3

9.4 12.7

18.2 21.3

44.3 37.6

100.0

::

13.9

17.8

15.4

22.4

28.6

100.0 100.0

1.9

17.9

17.2

13.8

21.9

27.3

100.0

2.3 1.8 1.6

18.2 16.0 16.9

14.6 15.5 18.3

11.8 13.4 14.7

20.3 22.9 23.4

32.9 30.5 25.1

2.8

23.5

17.9

12.4

18.7

24.7

25.0

21.2

21.8

14.1

26
Table 2. Percent distribution of live births by intervel since last live birth, according to educational attainment of mother, age of mother, and race:

Total of reporting areas, 1970 and 1977–Con.

[ Refers only to second and higher order live births]

1977 1970

Age of mother, Years of school completed by mother Years of school completed by mother

interval, and race

Ali O-8 9-11 12 13-15 16 yearsAll

years of years of. ~~5

9-11 12 13-15 16 years

schoolq

years years years years or more

school~

years years years or more

All races2–Con.

35-39 years

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

36-47 months . . . . . . . . . . .

46-71 months . . . . . . . . . . .

72 months and over . . . . . . .

40-49 years

Allintewals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

36-47 months . . . . . . . . . . .

48-71 months . . . . . . . . . . .

72 months and over . . . . . . .

White

Al I ages

All intervals . . . . . . . . . . . . .

Omonths (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

36-47 months . . . . . . . . . . .

46-71 months . . . . . . . . . . .

72 months and over . . . . . . .

Under 20 years

All intervals . . . . . . . ...<..

Omonths (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

36-47 months . . . . . . . . . . .

48-71 months . . . . . . . . . . .

72 months and over . . . . . . .

20-24 years

Ail intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

l-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

36-47 months . . . . . . . . . . .

48-71 months . . . . . . . . . . .

72 months and over . . . . . . .

Sea footnotas at end of table.

100.0 100.0 100.0 100.0 100.0 100.0

1.3

0.7

12.4

12.6

9.9

16.3

47.0

100.0

1.0

0.5

8.5

10.3

7.7

14.3

57.6

100.0

1.3

1.3

22.3

24.1

16.8

18.3

15.8

100.0

2.7

5.7

53.3

27.8

8.4

2.1

0.1

100.0

1.4

1.8

30.1

29.6

18.7

15.5

2.9

100.0

1.3

1.6

16.1

13.1

10.3

15.7

41.9

100.0

1.5

1.0

11.8

10.2

8.1

14,0

53.4

100.0

1.2

0.5

10.9

10.9

8.7

15.5

52.3

100.0

1.3

0.4 }

14.2

17.6

13.5

19.9

33.1

100.0

0.9

~o.5 }

9.4

13.6

11.3

16.3

48.1

100.0

1.6

0.6 }

21.7

100.0

1.6

14.7

13.7

11.2

19.0

39.8

100.0

1.2

10.2

12.3

9.9

17.9

48.5

100.0

2.8

27.1

100.0

1.5

16.1

16.5

14.7

20.6

30.6

100.0

1.0

10.4

12.9

11.4

21.4

42.8

100.0

2.1

29.0

28.8

16.9

14.3

8.9

100.0

5.3

31.6

31.6

15.8

15.8

100.0

5.9

49.5

27.6

10.0

5.7

1.4

1,2

0.4

12.1

13.1

10.3

16.9

46,0

2.2 1.8 1.4 1,3

19.3 14.9

15.9 13.3

11.6 10.2

18.4 17.7

32.6 42.0

12.8

12.6

10.8

19.2

43.2

14-.2

13.6

10.6

20.4

39.8

100.0

1.1

0.8

11.1

11.8

9.3

16.0

50.0

100.0

1.5

0.7

8.8

9.1

5.8

14.0

60.0

100.0

0.9

0.3

7.2

9.3

6.9

13.2

62.2

100.0

0.5

0.1

7.7

10.7

8.5

14.0

58.6

100.0 100.0 100.0 100.0

1.5 1.0

13.9 9.6

14.7 12.2

12.2 9.6

19.6 17.0

38.2 50.5

1.2

8.8

10.9

8.8

16.9

53.4

0.8

9.1

12.1

9.3

18.3

50.3

100.0

1.0

2.8

27.0

20.0

13.2

17.3

18.7

100.0

1.2

2.1

26.1

21.6

14.6

17.8

16.4

100.0

1.3

1.1

20.6

23,4

17,1

19.4

17.0

100.0

1.4

0.8

22.0

25.5

17.4

18.0

14.8

100.0 100.0

3.7 3.5

29.9 28.7

20.8 21.9

13.3 14.5

16.0 16.5

16.3 14.8

100.0 100.0

2.7 2.5

25.5

23.9

16.5

17.6

14.0

27.7

26.3

16.7

15.7

11.3

29.6 . 24.0

19.6 15.9

16.2 16.7

10.8 13.5

100.0

1.4

6.1

49.6

27.4

11.2

4.1

0.2

100.0

2.3

5.4

54.3

28.4

8.0

1.5

0.1

100.0

4.4

6.0

53.6

26.2

7.6

2.1

0.1

100.0

9.9

4.6

42.9

28.1

8.4

5.2

0.9

100.0 100.0 100.0 100.0

8.7 9.5

56.8 60.3

24.7 24.2

7.6 4.9

1.8 0.8

0.3 0.3

100.0 100.0

●12;} 10.3 13.5

61.6

18.3

4.5

1,3

0.7

16.2

48.6

27.1

6.2

1.4

0.5

*37.5 59.7

*37.5 23.2

*1 2.5 5.3

*. 1.1

*. 0.4

100.0

1.0

3.4

31.4

24.5

16.3

18.2

5.2

100.0

1.0

1.9

26.7

26.3

19.7

20.0

4.4

100.0

1.4

1.6

29.6

31.5

19.3

14.5

2.1

100.0

2.2

1.7

38.4

31.4

15.0

9.5

1.9

100.0 100.0 100.0 100.0

5.0 3.5

38.8 32.7

26.0 28.1

14.7 18.6

12.5 14.5

3.0 2.6

100.0 100.0

4.3

2.2 I

3.9 3.9 4.1

46.4 36.9

27.4 30.3

9.9 16.9

7.6 10.4

2.2 1.6

42.8

32.1

14.5

5.8

0.8

37.0

31.6

17.2

9.3

1.0

30
Table 2. Percent distribution of Iivebkthsby interval since last live biflh, amording coeducational attainment ofmother, ~ofmother, and race:

Total of reporting areas, 1970 and 1977–Con.

[ Refers only to second and higher order live births]

1977 1970

Age of mother,

interval, and race

Years of school compteted by mother Years of school completed by mother

All O-8 9-17 12 13-15 16 years

All

years of

G8 9-11 12 13-15 16 years

years

years of

schoolq

years years years or more

schooiq

yaars years years years or more

White–Con.

25-29 years

Al I intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

36-47 months . . . . . . . . . . .

4B-71 months . . . . . . . . . . .

72 months and over . . . . . . .

30-34 years

Allintewals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

36-47 months . . . . . . . . . . .

46-71 months . . . . . . . . . . .

72 months and over . . . . . . .

35-39 years

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

36-47 months . . . . . . . . . . .

4&71 months . . . . . . . . . . .

72 months and over . . . . . . .

4049 years

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

3647 months . . . . . . . . . . .

48-71 months . . . . . . . . . . .

72 months and over . . . . . . .

Black

All ages

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

3647 months . . . . . . . . . . .

48-71 months . . . . . . . . . . .

72 months and over . . . . . . .

See footnotes at end of table.

100.0

2.1

33.5

34.2

17.5

10.0

2.7

100.0

1.4

21.2

24.6

18.7

21.5

12.6

100.0

1.4

16.3

16.5

14.9

20.6

30.3

100.0

1.0

10.8

12.8

11.2

21.6

42.7

100.0

4.0

22.0

19,2

15.8

20.2

18.9

100.0

1.2

0.8

19.0

24.7

18.4

21.2

14.6

100.0

1.1

0.6

14.0

17.9

15.4

21.4

29.6

100.0

1.2

0.5

12.0

12.8

10.0

16.3

47.1

100.0

1.0

0.4

7.9

10.1

7.7

14.2

58.8

100.0

1.5

2.7

25.3

19.0

13.8

18.7

19.0

100.0 100.0 100.0

1.1

0.8

100.0

1.2

0.7

20.6

28.0

19.9

19.3

10.3

100.0

1.9

0.6 }

26.0

35.7

19.7

11.5

4.6

100.0

1.2

0.4 }

16.5

25.7

21.6

21.5

13.0

100.0

1.3

0.4 }

14.4

18.1

13.7

19.6

32.5

100.0

1.0

0.5 }

9.3

14.1

11.1

16.9

47.2

100.0

1.9

1.3 }

16.2

17.2

14.3

23.4

25.8

100.0

2.0

23.5

24.7

18.4

20.6

10.7

100.0

1.7

17.1

17.2

14.1

22.3

27.6

100.0

1.5

13.7

13.2

11.2

19.1

41.3

100.0

1.1

9.5

11.8

9.5

17.8

50.3

100.0

5.7

35.1

20.8

12.6

14.0

11.8

100.0 100.0 100.0 100.0

0.9 0.9

2.2 1.2 2.9 2.1 1.8 2.0

22.3 15.5

18.5 15.1

14.2 13.4

22.5 25.5

19.5 28.4

16.4

22.1

26.8

21.0

15.5

20.0

13.8

20.2

18.6

15.8

24.3

19.1

21.0

23.4

25.5

28.4

20.0

17.7

6.3

18.8

24.3

16.5

19.2

23.2

11.3

100.0 100.0 100.0 100.0

1.0

1.4

18.0

14.3

10.6

19.0

35.7

100.0

1.2

1.0

12,1

11.5

9.2

18.3

46.7

100.0

1.0

0.6

12.3

14.7

13.1

21.5

36.8

100.0

1.2

0.5

14.1

18.5

16.0

22.8

26.9

100.0

2.4 1.8 1.6 1.5

21.6

17.1

12.6

19.4

26.8

15.8

13.9

11.7

15.6

15.6

13.5

23.2

30.5

17.0

18.5

15.0

23.5

24.5

20.7

36.0

100.0

1.2

1.3

14.8

12.7

10.2

16.4

43.6

100.0

1.3

0.8

9.8

9.4

7.6

13.5

57.7

100.0 100.0

1.2

0.4

12.3

13.5

10.8

17.3

44.5

100.0 100.0 100.0 100.0

1.2

0.5

1.9

17.0

14.4

11.4

18.9

36.3

1.7

13.0

12.0

9.8

17.4

46.2

1.3 1.2

10.9

11.3

8.7

15.3

52.4

12.4

12.4

10.8

19.3

43.7

14.1

13.8

10.6

20.4

39.9

100.0 100.0

1.0 1.3

0.9 0.5

10.4

10.9 :::

8.6 5.7

16.1 12.7

52.0 64.3

100.0

0.8

0.3

$

.9

6:;

13.2

62.8

100.0

0.5

7.5

10.8

8.4

14.3

58.4

100.0 100.0 100,0 100.0

1.3 0.8 1.2 0.8

12.5

13.8

8.2

11.1

8.4

16.3

55.2

8.5

10.9

8.9

16.8

53.7

9.2

12.1

9.2

18.3

50.4

11.5

20.2

40.7

100.0

t .4

4.2

30.6

16.5

11.6

14.4

19.2

100.0

E

31.8

20.5

13.1

15.0

14.5

100.0

1.5

2.2

22.1

18.7

14.4

20.8

20.3

100.0

1.9

1.6

18.4

17.0

14.3

22.5

24.4

100.0 100.0 100.0 100.0

6.1

38.2

20.5

11.3

12.1

11.8

6.5 5.0 4.2

39.4

20.9

11.4

12.2

9.7

31.8

21.1

13.9

15.4

12.7

27.0

20.?

14.4

18.5

15.8

31
Tabla 2. ParCent distribution of Iiva bkths by interval since last live birth, according to educational attainment of mother, age of mother, and rata:

Total of reporting areas, 1970 and 1977–Con.

[ Rafers only to second and higher order live births]

1977 7970

Age of mother, Years of school completed by mother Years of school completed by mother

interval, and race

All O-8 $11 12 13-15 16 years

All

years of years of

O-8 9-11 12 13-15 16 years

school~

years years years years or more

school~

years years years years or more

Black–Con.

Under 20 years

AH intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

36-47 months . . . . . . . . . . .

46-71 months . . . . . . . . . . .

72monthsand over . . . . . . .

20-24 years

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

86-47 months . . . . . . . . . . .

4B-71 months . . . . . . . . . . .

72 months and over . . . . . . .

26-29 years

All intervals . . . . . . . . . . . . .

0 months (plural births] . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

3B47months . . . . . . . . . . .

46-71 months . . . . . . . . . . .

72 months andover . . . . . . .

30-34 years

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

I-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

24-35 months . . . . . . . . . . .

3B47 months . . . . . . . . . . .

46-71 months . . . . . . . . . . .

72monthsand over . . . . . . .

35-39 yaars

All intervals . . . . . . . . . . . . .

0 months (plural births) . . . .

l-n months . . . . . . . . . . . .

12-23 months . . . . . . . . . . .

2435 month$ . . . . . . . . . . .

36-47 months . . . . . . . . . . .

4B-71 months . . . . . . . . . . .

72monthsand over . . . . . . .

Saa footnotes at end of tabla.

100.0

2.3

6.5

50.8

25.7

10.7

3.9

0.1

100.0

1.4

3.0

28.8

23.0

17.4

20.3

6.2

100.0

1.4

1.7

17.1

15.7

13.4

24.0

26.7

100.0

1.4

1.2

14.2

12.4

10.4

19.6

40.9

100.0

1.4

1.1

13.1

11.2

B.6

15.5

49.0

100.0 100.0 100.0 100.0

2.2 2.0 2.7 4.9

8.0 6.8 5.6 3.3

53.5 52.6 47.1 33.2

21.5 25.8 28.7 27.4

9.6 9.6 12.5 21.6

5.1 3.1 5.2 8.8

0.2 0.1 0.1 0.7

100.0

:}

‘50.0

‘50.0

100.0

3.9

3.2 }

27.3

20.5

14.6

20.9

9.6

100.0

2.0

1.5 }

17.9

18.8

15.7

24.0

20.2

100.0

1.5

0.7 }

12.7

16.0

14.1

24.4

30.6

100.0

1.0

0.8 }

10.8

11.9

9.2

20.7

45.7

100.0

11.7

59.6

20.9

5.8

1.7

0.2

100.0

6.2

41.0

25.2

14.4

10.8

2.5

100.0

3.9

26.3

19.4

15.0

21.1

14.4

100.0

3.3

21.9

16.1

12.0

19.7

27.0

100.0

2.5

19.6

16.0

11.0

18.1

32.9

100.0 100.0 100.0 100.0 100.0

16.7

50.0

16.7

16.7

100.0

6.5

41.3

24.7

17.4

9.3

0.8

100.0

5.0

24.2

21.5

18.1

22.0

9.2

100.0

2.4

16.0

16.6

14.3

23.4

27.3

100.0

2.3

12.9

14.1

10.3

17.5

43.0

12.4 11.6

58.9 60.4

19.5 21.0

6.4 5.3

2.5 1.5

0.3 0.2

11.5 13.0

57.8

21.8

6.9

1.7

0.4

57.5

18.5

8.2

2.7

100.0 100.0

1.1 1.0

4.7 3.3

33.4 30.6

22.0 22.9

14.0 17.0

17.3 19.1

7.4 6.2

100.0

1.6

2.7

27.2

23.5

18.2

21.0

5.8

100.0

2.2

2.3

26.9

21.8

17.4

22.4

7.0

100.0 100.0 100.0 100.0

6,2 6.4

44.7 41.7

23.4 24.3

11.9 14.0

10.2 10.8

3.7 2.7

6.0

39.9

26.2

15.1

10.8

2.0

5.6

39.5

25.8

14.9

11.6

2.6

100.0 100.0

1.3

2.2

20.3

15.7

12.6

20.5

27.3

100.0

1.3

1.4

15.5

14.9

13.3

25.7

28.0

100.0

1.7

1.2

14.4

16.0

13.8

25.8

27.1

100.0 100.0 100.0 100.0

1.3

3.8

26.6

17.6

12.2

17.1

21.3

5.5 3.9 3.5 3.6

35.3 28.4

20.8 19.3

13.0 13.5

14.7 19.8

10.7 15.1

23.8

18.9

15.9

23.1

14.8

21.0

19.1

17.0

23.9

15.4

100.0

1.2

2.4

20.5

15.4

10.2

16.8

33.5

100.0

1.6

1.5

17.2

12.4

9.7

17.4

40.2

100.0

1.3

1.1

12.4

11.5

9.7

20.0

44.1

100.0

1.5

1.0

11.6

10.6

10.4

19.5

45.4

100.0 100.0 100.0 100.0

4.2 3.7 2.8 2.3

28.B 24.5

19.9 16.4

11.7 11.8

15.6 19.3

19.0 24.2

18.7

14.5

12.3

20.4

31.3

14.4

14.6

11.5

23.3

33.7

100.0 100.0

1.7 1.8

2.3 1.6

18.1 15.4

14.5 11.7

10.6 8.9

13.2 15.1

39.7 45.5

100.0 100.0

1.2

0.6 ~

10.9 9.4

10.2 9.4

7.8 7.3

16.1 14.0

53.2 57.7

100.0 100.0 100.0 100.0

3.2 2.5 1.9 2.5

25.2 21.1

18.8 17.0

i2.3 11.0

16.8 18.4

23.7 29.9

15.3

14.0

10.8

18.0

40.0

14.5

I 11.4

9.8

21.8

40.0

32
Table 2. Percant distribution of live births by interval since last live bitih, amording toedumtional attainment ofmother, ~of mother, andrece:

Total of reporting areas, 1970 and 1977-Con.

[Refers only to second and higher order live births]

1977 1970

Age of mother,

Years of school completed by mother Years of school completed by mother

interval, and race

All O-8 9-11 12 13-15 16 years

All

years of years of

0-8 9-11 12 13-15 16 years

years years years

schooll

years or more

schooll

years years years years or more

Black-Con.

40-49 years

All intervals . . . . . . . . . . . . . 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 months (plural births) . . . . 1.1 1.3 1.7 0.7 0.5

I-n months . . . . . . . . . . . . 0.6 0.5 1.1 0.2 0.5 :} 17 20 1-5 18 10 16

12-23 months . . . . . . . . . . . 10.4 12.4 11.4 8.5 9.4 5.4 13.8 17.1 13.5 11.1 7.7 8.2

24-35 months . . . . . . . . . . . 10.5 13.0 10.1 10.7 8.5 6.8 14.3 16.8 15.5 10.2 11.5 11.5

36-47 months . . . . . . . . . . . 7.4 10.5 6.0 6.6 8.0 9.5 11.7 13.4 13.1 8.1 9.6 16.4

4B-71 months . . . . . . . . . . . 14.6 15.9 16.2 12.7 12.7 14.2 18.3 17.9 19.2 17.4 19.2 19.7

72 months and ovar . . . . . . . 55.5 46.3 53.5 60.7 60.6 84.2 40.2 32.9 37.2 51.4 51.0 42.6

1 Includes births to mothers with years Of =hool nOt **d.

z,ncl”d~ ra=es other then white and black.

33
Table 3. Mean interval since termination of last pregnancy by outcome of last pregnancy, age of mother, live-birth order, and race:

Total of 43 reporting States and the District of Columbia, 1977

[Refers only to live births resufting from second and higher order pregnancies]

All previous pregnancies Last pregnancy, live birth Last pregnancy, fetal death

Age of mo ther and live birth order

All races2 White Black All races2 White Black All races2 White Black

All ages

All birth Orders . . . . . . . . . . . . . . . . . . . . . . . . .

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

Secondbirths . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

Fifth andhigherorder births . . . . . . . . . . . . . . . .

Under20years

All birthorders . . . . . . . . . . . . . . . . . . . . . . . . .

First births . . . . . . . . . . . . . . . . . . . .’ . . . . . . . .

Secondbirths . . . . . . . . . . . . . . . . . . . . .. . . . . .

Thirdbirths . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

Fifth andhigher ordar births . . . . . . . . . . . . . . . .

20-24years

All birthwders . . . . . . . . . . . . . . . . . . . . . . . . .

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

Secondbirths . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

Fifthandhigherorderbirths . . . . . . . . . . . . . . . .

25-29 years

All birth orders . . . . . . . . . . . . . . . . . . . . . . . . .

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

Secondbirths . . . . . . . . . . . . . . . . . . . . . . . . . .

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

Fourth births . . . . . . ..j . . . . . . . . . . . . . . . . . .

Fifth andhigherOrder births . . . . . . . . . . . . . . . .

30-34 years

All birth orders . . . . . . . . . . . . . . . . . . . . . . . . .

Firstbirths . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Secondbirths . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

Fifthand higherorderbirths . . . . . . . . . . . . . . . .

35-39years

Allbirthorders . . . . . . . . . . . . . . . . . . . . . . . . .

First births . .’ . . . . . . . . . . . . . . . . . . . . . . . . . .

%condbirths . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

Fifth andhigherorderbirths . . . . . . . . . . . . . . . .

40-49years

All birth orders . . . . . . . . . . . . . . . . . . . . . . . . .

Firstbirths . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Secondbirths . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

Fifth andhigher order births . . . . . . . . . . . . . . . .

42.1

27.7

40.5

45.3

48.3

46.8

22.3

20.5

23.0

20.2

18.4

17.7

32.2

26.4

34.2

29.6

25.5

23.1

42.6

30.8

44.9

43.6

37.3

31.3

54.3

36.2

54.8

59.9

54.0

43.8

71.1

44.1

71.0

82.8

79.3

60.3

88.9

52.7

95.9

113.8

110.9

78.0

41.8

27.5

40.0

45.6

46.9

47.3

22.0

20.1

22.6

19.8

18.3

18.7

31.6

25.9

33.4

29.0

25.0

23.0

41.7

30.3

43.5

42.7

36.2

30.6

53.5

35.8

53.4

59.2

52.7

42.6

70.8

42.1

69.4

82.9

79.1

59.6

90.3

51.8

94,0

116.5

111.9

78.6

43.7

29.1

44.0

44.3

44.6

46.2

23.2

22.0

24.0

20.7

18.4

16.9

34.6

28.2

38.9

31.5

26.5

23.2

50.0

36.2

58.9

50.5

42.3

32.9

63.3

42.5

73.5

70.1

63.7

48.2

75.7

55.6

90.4

91.4

84.0

63.9

86.4

*70.7

119.8

108.1

112.1

78.1

Mean interval (in months)

44.0

4i:+

46.6

47.7

48.0

22.8

23:3

20.3

18.5

17.6

33.3

. . .

35.0

30.2

25.9

23.3

44.5

.,.

46.4

44.9

38.3

31.9

56.9

5+:2

62.3

56.1

44.9

74.5

74:7

87.1

83.3

62.0

92.6

. . .

102.6

121.9

116.2

80.1

43.8

. . .

41.2

47,0

48.4

48.5

22.5

228

19.9

18.5

18.7

32.8

. . .

34.2

29,5

25.4

23.2

43.5

.,.

45,1

44.0

37.1

31.2

56.0

. . .

55.8

61.6

54.8

43.7

74.4

. . .

73.1

87.4

83.1

61.5

94.5

. . .

100.7

124.7

117.7

81.1

45.7

. . .

45.3

45.6

45.8

47.2

23.5

. . .

24.3

20.9

18.5

16.8

35.9

40:0

32.3

27.0

23.5

52.2

. . .

61.4

52.3

43.6

33.6

66.1

. . .

76.9

73.1

66.3

49.4

78.5

958

95.7

88.2

65.0

88.4

1279

114.4

115.4

79.4

25.4

27.7

22.1

24.8

25.4

26.6

19.7

20.5

15.9

15.4

14.7

* 24.0

23.3

26.4

19.3

18.4

17.4

16.1

25.6

30.8

22.4

22.9

21.1

20.1

29.0

36.2

26.4

28.5

25.9

24.6

37.1

44.1

35.4

39.7

36.4

31.6

45.7

52.7

43.5

50.2

51.9

40.4

25.2

27,5

21.8

24.9

25.5

26.7

19.4

20.1

15,6

15.0

*14.8

*21.O

23.0

25,9

18,8

17,9

17.0

16,3

25.2

30.3

21.7

22.3

20.7

19.5

28.6

35.8

26.0

28.1

25.3

24.0

36.4

42,,1

34,9

39.6

36.3

30.8

45.7

51.8

43,,2

52.5

50.0

40.4

26.8

28.1

24.6

25.1

25.5

26.7

20.8

22.0

16.7

16,0

*1 5.0

* 27.0

24.6

29.2

21.7

19.7

17.9

16.2

29.0

36.2

28.1

25.9

23.3

2i.0

33.4

42.5

32.5

32.8

30.9

27.0

42.4

55.6

40.9

44.4

37.8

37.4

49.6

●70.7

55.3

45.9

‘68.1

41.8

lln~luda~birth~ forv,jhi~h the~utc~ma~f the~otharn~la~pregnancy i~unkno~n.

zln~ludes ~acgs tythar than whita and black.

34
Table4. Percent distribution of Iivebirths byintarval sinca termination of latipregnancy, -orting tooutcome oflastpregnancy, age of mother,

andrece: Total of reporting areas, 1970and 1977

[Rafers onlv to live births resulting from sacond and higher ordar pregnancies]

All previous Last pregnancy, Last pregnancy,

Age of mother, interval, and race

pregnancies live birth fetal death

1977 1970 1977 1970 1977 1970

All races2

All ages

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (plural births) . . . . . . . . . . . . . . . .

l-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

3647months . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . .

OOmonthsandover . . . . . . . . . . . . . . . . . . .

Under20yeers

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (plural births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

3647months . ... . . . . . .. . . ..~ .. . ..~..~. .

48-59months, . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

20-24years

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (pluralbirths) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . .

OOmonthsandover . . . . . . . . . . . . . . . . . . .

25-29yeers

Allintarvals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (plumlbirths) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

30-34 years

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths(plural births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

3647months . . . . . . . . . . . . . . . . . . . . . . .

46-59months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

Sea footnotes at end of table.

100.0

1.3

3.0 1

13.6

13.8

22.9

15.1

9.8

20.5

100.0

2.2

8.1

31.0

23.1

24.8

8.2

2.1

0.5

100.0

1.4

3.7 I

17.0

16.9

27.0

16.6

9.6

7.9

100.0

1.2

2.3 )

10.9

12.3

23.2

16.5

11.2

22.4

100.0

1.2

1.8 }

8.7

9.7

18.0

14.3

10.8

35.5

100.0

4.4

16.3

15.1

23.4

14.5

8.9

17.4

100.0

12.2

36.7

23.6

21.0

5.1

0.9

0.5

100.0

5.5

20.9

18.8

28.5

15.3

6.7

4.2

100.0

3.3

13.3

13.6

23.8

16.9

11.3

17.8

100.0

2.7

10.3

10.6

17.7

13.4

11.1

34.2

100.0

1.5

1.7 }

11.1

13.5

23.7

16.0

10.5

22.1

100.0

2.6

6.3

29.8

24.0

26.1

8.6

2.2

0.5

100.0

1.5

2.2 }

14.7

16.9

28.3

17.6

10.3

8.4

100.0

1.3

1.1 }

12

24.1

17.5

12.0

24.0

100.0

1.3

0.8 }

6.3

9.1

18.2

14.9

11.4

38.0

100.0

3.5

14.8

14.9

24.0

15.2

9.3

18.3

100.0

11.0

36.0

24.2

22.0

5.3

1.0

0.5

100.0

4.5

19.3

18.9

28.6

16.1

7.1

4.4

100.0

2.4

11.4

13.3

24.5

17.8

11.8

18.8

100.0

2.1

8.9

10.1

17.7

13.7

11.5

35.9

100.0

0.2

14.1 }

34.6

16.3

16.0

7.5

4.4

7.0

100.0

0.3

17.6

37.6

18.3

17.5

6.2

1.8

0.6

100.0

0.2

15.1 }

34.8

16.2

16.8

8.2

4.6

4.1

100.0

0.2

13.9 }

35.6

16.0

14.8

6.9

4.5

8.2

100.0

0.2

11.9 }

33.2

16.2

15.7

7.5

4.5

10.8

100.0

14.8

35.1

17.2

16.1

6.5

3.8

6.5

100.0

25.8

44.0

16.9

9.9

2.7

0.3

0.4

100.0

18.0

39.3

17.9

15.9

5.2

2.2

1.5

100.0

13.7

35.3

17.7

16.3

6.8

4.2

6.1

100.0

10.0

28.3

16.4

17.8

8.7

6.0

12.9

35
Table4. Percent distribution of Iivebirths byinterval since termination of Iastpregnancy, according tooutcomeof Iastpregnancy, age of mother,

andraca: Total of reporting areas, 1970 and 1977—Con.

[ Refars only to live births resulting from second and higher order pregnancies]

All previous Last pregnancy, Last pregnancy,

pregnancies live birth fetal death Age of mother, interval, and race

1977 1970 1977 1970 1977 1970

All races2–Con.

35-39 years

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (plural births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35 months . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandovar . . . . . . . . . . . . . . . . . . .

100.0

1.3

1.5 I

8.0

8.5

13.8

9.9

8.3

48.6

100.0 100.0

1.4

0.8 I

6.1

7.8

13.5

10.1

8.6

51,6

100.0 100.0

0.2

8.7 t

27.5

15.3

16.7

7.9

5.7

17.9

100.0

7.1

23.5

14.2

19.1

9.3

6.6

20.0

2.2

8.5

9.0

14.6

11.1

9.7

44.9

1.8

7.3

8.6

14.2

11.3

9.9

46.8

40-49 years

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (plural births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

100.0

0.5

7.0 }

18.5

17,4

15.7

10.5

6.1

24.3

100.0

4.6

20.4

13.2

16.3

10.9

8.7

25.9

100.0

1.1

1.0 1

5.2

6.7

11.8

8.6

7.4

58.2

100.0 100.0

1.1

0.5 }

4.1

5.7

11.5

8.4

7.5

61.1

100.0

1.6

5.9

1.3

4.8

6.8

12.9

10.4

9.8

54.1

7.3

13.1

10.4

9.7

52.1

White

All agas

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

1~-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . .

60monthsand over . . . . . . . . . . . . . . . . . . .

100.0

1.3

2.8 t

13.1

13.8

23.7

15.5

9.8

19.9

100.0 100.0

1.4

1.4 }

10.5

13.6

24.6

16.5

10.5

21.5

100.0 100.0

0.2

14.4 1

35.4

16.0

15.6

7.3

4.2

7.0

100.0

14.9

35.5

17.2

15.9

6.4

3.8

6.3

4.1 3.1

13.8

14.7

24.5

15.7

9.6

18.6

15.5

14.9

23.8

14.9

9.1

17.7

Under 20years

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

100.0

2.2

8.1 I

31.5

23.5

25.0

7.6

1.7

0.4

100.0 100.0

2.7

6.0 }

30.0

24.7

26.7

7.9

1.7

0.3

100.0 100.0

0.3

18.3 1

38.6

17.8

17.0

5.9

1.6

0.6

100.0

28.7

45.5

16.3

8.7

2.2

0.3

0.3

12.1

36.5

23.8

21.5

4.9

0.8

0.5

10.5

35.5

24.6

22.9

5.2

0.8

0.5

20-24 years

Allintervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (plurelbirths) . . . . . . . . . . . . . . . .

I-n months . . . . . .’....... . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

100.0 100.0

0.1

15.6 t

35.6

15.8

16.3

8.0

4.6

4.0

100.0

18.2

39.9

18.1

15.3

5.0

2.2

1.4

100.0

1.3

3.6 }

16.9

17.2

28.0

16.7

9.3

7.0

100.0 100.0

1.5

2.0 1

14.4

17.4

29.6

17.9

9.9

7.4

5.3

20.3

18.8

29.2

15.6

6.7

4.0

4.1

18.6

18.9

30.5

16.5

7.1

4.3

See footnotes at end of table.

36
Tabla4. Percent distribution of Iivebirths byinterval since termination of lastpregnancy, according tooutcome oflastpregnancy, age of mother,

and race: Total of reporting areas, 1970and 1977-Con.

[Refers only to live births resulting from second end higher order pregnancies]

All previous Last pregnancy, Last pregnancy,

Age of mother, interval, and race

pregnancies live birth fetal death

1977 1970 1977 7970 1977 1970

White-Con.

25-29 years

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (plural births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

3B47months . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

30-34 years

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omcmths(plurel births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . .

16-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

35-39years

Allintewals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths(plural births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

3647mmths . . . . . . . . . . . . . . . . . . . . . . .

4B-59months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

40-49 years

Allintewals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths(plural births] . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . .

46-59months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandovar . . . . . . . . . . . . . . . . . . .

Black

All ages

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omont’hs(plurel births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

3647months . . . . . . . . . . . . . . . . . . . . . . .

46-59months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

See footnotes at end of table.

100.0

1.2

2.2 }

10.7

12.6

24.2

17.0

11.2

20.9

100.0

1.2

1.8 }

8.6

9.9

18.5

14.7

10.9

34.5

100.0

1.3

1.4 }

::;

14.1

10.0

8.3

46.4

100.0

1.0

1.0 I

5.0

6.5

11.8

8.6

7.5

56.7

100.0

1.6

3.8

15.5

13.2

19.2

13.2

9.8

23.7

100.0

3.1

12.9

13.7

24.3

17.3

11.3

17.4

100.0

2.5

9.8

10.4

17.8

13.6

11.3

34.6

100.0

2.1

8.1

8.7

14.1

11.1

9.7

46.2

100.0

1.5

5.6

7.0

12.7

10.0

9.7

53.6

100.0

6.3

21.0

15.9

20.8

12.2

7.9

15.9

100.0

1.3

0.9 t

8.0

12.3

25.2

18.1

11.9

22.3

100.0

1.3

0.7 }

6.0

9.2

18.8

15.4

11.6

36.9

100.0

1.4

0.7 }

5.7

8.0

13.8

10.2

8.6

51.6

100.0

1.0

0.4 }

3.6

5.5

11.4

8.5

7.7

62.0

100.0

1.7

2.9.

13.9

12.7

19.3

13.7

10.3

25.6

100.0

2.2

10.9

13.4

25.0

18.1

11.9

16.4

100.0

1.9

8.3

9.9

17.8

14.0

11.7

36.4

100.0

1.7

6.8

8.3

13.6

11.2

9.9

46.5

100.0

1.3

4.4

6.5

12.3

10.0

9.7

55.9

100.0

5.9

20.3

15.9

21.0

12.4

8.1

16.4

100.0

0.2

14.3 t

36.4

15.8

14.4

6.7

4.2

8.0

100.0

0.2

12.0 t

34.0

16.1

15.4

7.3

4.4

10.6

100.0

0.2

8.9 I

28.1

15.7

16.3

7.8

5.6

17.4

100.0

0.6

6.7 }

19.0

16.7

16.0

10.6

6.1

24.4

100.0

0.3

12.2 }

30.6

17.6

18.3

8.7

5.2

7.3

100.0

13.8

35.9

17.7

16.2

6.7

4.7

5.5

100.0

10.2

28.2

16.5

17.8

8.6

6.0

12.6

100.0

7.3

23.6

14.1

19.2

9.2

6.6

20.0

100.0

4.7

20.0

13.4

16.4

10.7

8.9

25.8

100.0

14.1

31.5

16.8

17.8

7.6

3.8

8.4

37
Table4. Percent distribution of Iivebirths byinterval sinca termination of last pregnancy, according tooutcome oflastprqnancy, aget>f mothar,

and race: Total of reporting areas, 1970 and 1977–Con.

[Refers only’ to live births resulting from second and higher order pregnancies]

All previous Last pregnancy, Last pregnancy,

Age of mother, interval, and race

pregnancies live birth fetal death

1977 1970 1977 1970 1977 1970

Black–Con.

Under 20 years

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (plural births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

20-24 years

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (pluralbirths) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . .

60monthsand over . . . . . . . . . . . . . . . . . . .

25-29yeers

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths(plural births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35 months . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandovar . . . . . . . . . . . . . . . . . . .

30-34 yaars

Allintervals . . . . . . . . . . . . . . . . . . . . . . . .

Omorwhs (plural births) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . .

36-47 months . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . .

35-39yeers

All intervals . . . . . . . . . . . . . . . . . . . . . . . .

Omonths (pluralbirths) . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . .

18-23 months, . . . . . . . . . . . . . . . . . . . . . .

24-35 months . . . . . . . . . . . . . . . . . . . . . . .

3647 months . . . . . . . . . . . . . . . . . . . . . . .

48-59 months . . . . . . . . . . . . . . . . . . . . . . .

60 monthsandover . . . . . . . . . . . . . . . . . . .

See footnotes et end of tabla.

100.0

2.2

7.8 t

29.7

22.4

24.6

9.7

3.0

0.7

100.0

1.5

4.2 }

16.9

15.1

22.6

16.2

11.4

12.1

100.0

1.4

2.7 }

10.9

9.5

16.1

13.2

11.7

34.4

100.0

1.4

1.9 }

9.2

8.4

13.2

10.4

9.3

46.2

100.0

1.5

1.7 }

8.7

7.0

12.4

8.9

7.7

52.2

100.0

12.4

36.9

23.0

20.3

5.6

1.2

0.6

100.0

6.9

23.7 \

18.5

24.9

13.8

7.0

5.3

100.0

4.5

15.6

12.3

19,2

14.5

11.6

22.2

100.0

3.7

12.5

11.2

16.5

11.4

10.0

34.6

100.0

2.9

10.9

10.4

16.7

11.3

9.4

38.3

100.0

2.5

6.7 }

28.9

22.8

25.3

10.0

3.1

0.7

100.0

1.6

3.1 t

15.2

14.7

23.1

17.0

12.2

13.0

100.0

1.6

1.8 }

9.1

8.8

16.0

13.7

12.2

36.9

100.0

1.5

1.3 I

7.6

7.6

12.8

10.5

9.5

49.2

100.0

1.6

1.3 t

7.5

6.5

11.9

8.9

7.8

54.5

100.0

11.8

36.8

23.3

20.6

5.7

1.3

0.6

100.0

6.3

23.0

18.7

25.2

14.2

7.3

5.4

100.0

4.0

14.7

12.0

19.3

15.0

12.1

22.9

100.0

3.5

11.7

11.0

16.4

11.5

10.2

35.7

100.0

2.7

10.4

10.1

16.6

11.3

9.6

39.3

100.0

0.3

15.0 t

35.1

19.7

19.5

7.1

2.5

0.7

100.0

0.3

12.9 }

31.3

17.9

18.6

9.3

5.1

4.6

100.0

0.2

11.3 }

29.2

16.7

17.3

8.4

6.5

10.4

100.0

0.1

8.9 }

26.9

16.0

17.8

9.9

6.3

14.1

100.0

0.2

6.6 t

23.3

13.1

18.3

8.7

6.6

23.2

100.0

22.6

38.9

18.6

14.3

4.6

0.4

0.6

100.0

16.6

34.8

16.5

19.9

6.9

2.5

2.7

100.0

12.1

28.7

17.3

16.6

8.1

5.0

12.3

100.0

7.2

26.8

15.3

17.8

9.7

6.6

16.5

100.0

5.7

19.8

16.4

19.0

11.3

7.1

20.7

38
Table 4. Percent distribution of live births by interval sinoa termination of last pregnancy, aooording to outcome of last pregnancy, age of mother,

and ram Total of reporting areas, 1970 and 1977-Con.

[Rafars Onlv to live births resulting from saoond and highar order preenanciasl

Age of mother, interval, and rata

All previous Last pregnancy, Last pregnancy,

pragnarrcias~ live birth fetal death

1977 1970 1977 7970 1977 7970

Blaok-Con.

40-49 years

All intervals . . . . . . . . . . . . . . . . . . . . . . . . 100.0 100.0 100.0 100.0 100.0 100.0

0 months (plurel births) . . . . . . . . . . . . . . . . 1.3

}

1.7 1.4

I-n months . . . . . . . . . . . . . . . . . . . . . . . . 1.2 0.7 t

1.7 9.9-} 3.2

12-17 months . . . . . . . . . . . . . . . . . . . . . . . 5.4 7.3 5.0 6.5 12.7 23.4

18-23 months . . . . . . . . . . . . . . . . . . . . . . . 7.1 8.4 6.6 8.4 16.2 9.6

24-35 months . . . . . . . . . . . . . . . . . . . . . . . 11.7 15.2 11.4 15.2 17.6 14.9

3647months . . . . . . . . . . . . . . . . . . . . . . . 8.0 12.1 7.9 12.1 9.2 12.8

48-58 months . . . . . . . . . . . . . . . . . . . . . . . 9.7 9.8 7.0 7.4

60monthsand ovar . . . . . . . . . . . . . . . . . . . 2: 45.6 2: 46.3 27.5 28.7

1 lncludm bir~s f or which the ~tcome of the mothar% last pregnancy is unknown.

21nc;udes r~em other than whim ●nd black.

39
.-..

Table 5. Percent of infants of low birth weight, by educational attainment of mother, outcome of last pregnancy, interval since termination of

last pregnancy, and race: Total of 41 reporting States and the District of Columbia, 1977

[Rafars only to live births resuking from second and higher order pregnancies. Excludes plural births]

Yearsof school completed by mother

Outcome of last pregnancy, interval since termination of last

pregnancy, and race All yeers G8 9-11 12 13-15 16 years

of scisool~ vears vears vears vears or more

All previous pregnancies

All races3

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

l-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

White

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Black

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

l-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3647months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Last pregnancy, live birth

All races3

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

lB-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35 months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

38-47months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4B-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

White

All intewals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

l-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

See footnotes at and of table.

5.6

15.6

7.1

5.4

4.6

4.5

4.6

5.6

4.5

12.8

5.6

4.3

3.7

3.7

3.8

4.7

10.9

25.8

13.2

11.0

9.9

9.2

8.8

9.5

5,3

20.2

7.4

5.1

4.3

4.3

4.5

5.5

4.2

16.9

5.7

4.0

3.5

3.5

3.6

4.6

7.7

18.8

8.9

7.3

6.4

6.5

6.6

7.0

6.8

17.0

7.5

6.3

5.8

6.1

5.8

6.3

12.0

24.7

14.9

12.2

9.7

8.6

10.6

10.5

7.5

20.4

9.1

7.2

6.1

6.3

6.5

6.9

6.5

18.4

7.6

6.2

5.5

5.8

5.8

6.1

8.7

21.6

10.5

8.5

7.5

7.1

6.7

7.6

6.9

17.9

8.4

6.8

6.1

5.8

5.5

6.4

13.1

28.9

15.3

12.7

11.6

11.1

9.9

11.2

8.3

26.0

10.7

8.2

7.2

6.9

6.4

7.5

6.6

21.5

8.4

6.6

5.8

6.5

5.4

6.3

5.1

14.0

6.3

4.9

4.2

4.2

4.3

5.3

4.2

11.6

5.0

4.0

3.5

3.5

3.5

4.4

10.0

23.9

11.9

9.9

9.3

8.7

8.3

9.2

4.8

17.8

6.3

4.6

4.0

4.0

4.1

5.1

3.8

14.7

5.0

3.7

3.2

3.3

3.4

4.2

4.2

11.8

5.0

3.7

3.3

3.6

3.9

4.7

3.5

9.9

4.2

3.1

2.8

3.1

3.2

3.9

8.9

22.4

10.0

9.1

8.0

7.5

8.2

8.3

3.8

16.3

4.9

3.4

3.0

3.4

3.7

4.5

3.2

13.7

4.1

2.9

2.5

2.9

3.1

3.8

3.2

8.6

4.0

2.9

2.7

2.5

3.0

4.0

2.9

7.8

3.7

2.7

2.5

2.3

2.5

3.5

6.7

16.1

7.1

5.9

6.5

5.3

7.2

6.6

2.9

10.9

4.0

2.5

2.5

2.4

2.7

3.7

2.6

10.8

3.7

2.4

2.3

2.2

2.3

3.3

40
Tabie5. Percent of infants of low birth weight, byed~mtional attainment ofmother, outcome of Iastpregnancy, interval since-terminationof

lastpregnancy, andrace:Totalof41 reporting States andthe District of Columbia, l977-Con.

[Refers only to live births resulting from second and higher order pregnancies. Excludas plural births]

Years of school completed by mother

Outcome of last pregnancy, interval since termination of last

pregnancy, and race All yaars O-8 9-T1 12 13-15 16 years

of school ~ years years years years or more

Last pregnancy, live birth-Con.

Black

Ail intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Last pregnancy, fetal death

All races3

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3B-47months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4B-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

White

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36-47months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Black

All intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-n months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12-17months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-23months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24-35months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3647months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48-59months . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60monthsandover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10.5

27.7

13.3

10.6

9.6

8.9

8.5

9.3

7.9

11.6

6.4

7.2

7.8

8.1

8.0

9.1

6.7

9.9

5.4

5.9

6.7

7.1

6.4

7.9

14.4

21.9

12.8

13.5

13.1

12.9

14.4

15.5

11.7

26.2

14.7

12.1

9.4

8.2

10.4

10.6

10.2

14.9

8.2

8.9

9.5

11.8

9.1

12.9

9.5

14.4

6.9

8.0

9.3

11.6

7.3

13.6

15.6

18.9

16.8

13.3

14.4

16.1

13.8

10.0

12.7

30.2

15.4

12.3

11.3

10.9

9.5

11.1

11.1

16.4

9.8

10.1

10.4

10.9

11.4

11.2

9.3

13.6

8.4

7.9

8.7

9.6

9.1

9.2

16.9

25.1

14.4

16.4

15.8

15.3

17.9

17.0

9.6

26.0

11.7

9.5

9.0

8.4

8.0

9.0

7.5

11.0

6.1

7.1

7.2

7.5

:;

6.5

9.6

5.1

6.1

6.3

6.5

6.3

8.2

13.5

20.2

12.5

12.2

11.9

12.7

13.2

15.2

8.2

23.4

9.8

8.5

7.3

7.3

7.7

7.8

6.6

9.7

5.1

5.5

7.1

7.1

6.6

8.5

5.6

8.3

4.5

4.4

6.3

6.7

4.9

6.6

12.8

21.3

10.4

11.5

11.2

9.7

13.9

18.4

5.9

15.3

5.7

4.3

5.7

4.4

6.6

6.4

5.4

7.9

4.0

4.9

5.8

6.3

7.2

6.9

4.8

7.0

3.7

4.2

5.2

5.1

5.7

6.5

11.5

16.7

9.3

11.8

11.5

13.5

13.8

9.4

lln~lude~births tom~thers with ymrsof ~hool notsmted.

Zlncludes births for which tha outcome of themothar’s laetpragnancY isunlmown.

31ncluda$ racas ~fier than ~hita and bleck.

41
Appendix

Contents

Technical notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

List of appendix tables

1. Areas reportingdatesof,lastlivebirth and lastfetel death, 1970-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Il. Percent of records with information missing forintewal since lastlive tirth, intewal sinmtermination of last pregnancy,

and outcome of last pregnancy, by race: Total of reporting areas, 1970-77 ,. ...,,.0 . . . . . . . . . . ...0.... . . . . 45

1I 1, States with data based on 100 percent of births received through the Cooperative Health Statistics System, 1972-77 ... . 46

42
Technical notes

Sources of data

Data presented in this report were ‘obtained from

information reported on the birth certificates ffled in

each of the registration areas of the United States

that requested the dates of the mother’s last live birth

and last fetal death. Additional birth statistics are

published annually by the National Center for Heath

Statistics in Volume I of Vital Statistics of the United

States. The Technical appendix of these volumes provides a complete discussion of the derivation of these

statistics.

Reporting areas

The dates of the last live birth and the last fetal

death (which are used to compute the interbirth

intervals) were added to the U.S. Standard Certificate

of Live Birth in 1968. Tabulations of data from these

items were first presented in 1969. However, because

the focus of this report is on changing interbirth

intervals during the 1970’s, data for 1969 are not

included in this report.

In 1970, information was obtained frpm 38

States on the date of the last live birth and from 37

States on the date of the last fetal death. By 1977,

the number of areas reporting these items had

expanded to include 43 States and the District of

Columbia (see table I).

When birth intervals are tabulated in conjunction

with other characteristics (such as mother’s educational attainment and period of gestation) that are

not reported on the birth certificates of all States, the

size of the reporting area may be reduced. This occurs

because although the dates of the last live birth and

the last fetal death are requested on the birth certificates, information on the other variables is not.

Therefore, statistics may vary slightly from one table

to another as a result of variations in the reporting

areas. For example, the mean interval since the last

live birth is 45.5 for the 43 States and the District of

Columbia reporting the date of the last live birth and

45.6 for the 41 States and the District of Columbia

reporting the date of the last live birth and educational attainment of mother.

Changes in composition of reporting areas.–Comparisons of data for 1970 and 1977 can be made

although statistics for these years are based on a different number of reporting States. The percent distribution of births by interval since the last live birth in

1977 is virtually the same as the distribution that

would have prevailed if the States in the reporting

area had not changed since 1970.

Completeness of reporting

Data used to compute interbirth intervals were

more fidly reported in 1977 than in 1970 as shown in

table II. Levels of reporting were also higher for white

than for black births.

Births for which interval information is missing

and for which birth order is not stated are excluded

from the computation of means and percent distributions.

Computation of intervals

Intervals since the last live birth and the last fetal

death are computed from the date of birth, the date

of the last live birth, and the date of the last fetal

death. The interval since the mother’s last live birth is

the difference in months between the date of the last

live birth and the date of the present birth. The

interval since the last fetal death is the difference in

months between the date of the last fetal death and

the present birth. Both the month and year of the last

live birth or fetal death must be valid for an interval

to be computed.

Data on the interval since the termination of the

last pregnancy are derived from the computed intervals since the last live birth and the last fetal death.

A calculated interval of O months since the last

live birth indicates the second born of a set of twins,

43
Table 1. Areas reporting dates of last I ive birth and last f etal death, 1970-77

[ Unless otherwisa no tad, araas also reported aducationd attainment of mother and date of last normal manstrual period 1

3tate 1977 1976 1975 1974 1973 1972 1971 1970

Alabama . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Arizona . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Arkansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

California . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Connecticut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Delaware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DistrictofColumbia .,..,.... . . . . . . . . . . . . . . . . . . . . . . . . .

Florida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hawaii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Idaho..................”. . . . . . . . . . . . . . . . . . . . . . . . . .

Illinois . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Iowa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Massachusetts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Michigan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Missouri . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Montana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nebraska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Hampshire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Jersey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NawMexico . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New York . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

North Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

North Dakota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Oklahoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

PannWlvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rhode Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

South Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

South Dakota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tennessee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Washington . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

West Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wyoming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

x

x

x

lx

x

2X

x

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2X

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1 Did “CIt r~p~rt aducatio”al attainment of parants.

2Did not raport data of last menstrual pariod.

3Cartificate requested only date of last live birth.

44
Table Il. Percent ofrecords with information missing forintewal sinmlast live timh, interval sina termination of Iastpregnancy,

and outcome of last pregnancy, by race: Total of reporting areas, 1970-77

[Refers Only m live births rawltiw from second and higher order pregnancies]

Interval since last Interval since termination Outcome of last

Yeer

live birth of last pregnancy pregnancy

.

All mcesq White Black All racesq White Black All racesq White Black

1977 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1

1976 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3

1975 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6

1974 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5

1973 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.8

1972 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.9

1971 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.9

1970 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.6

4.8 6.5 11.4 10.5 15.5 5.7 5.1 8.2

5.0 6.9 11.3 10.5 15.1 5.5 5.1 7.7

5.2 7.6 11.2 10.4 15.0 5.1 4.7 7.0

5.2 7.1 10.7 10.1 13.8 4.9 4.6 6.3

5.5 7.9 11.2 10.6 14.7 5.2 4.9 6.7

5.6 7.6 11.1 106 14.2 5.2 5.0 6.7

5.6 7.9 10.9 10.4 13.8 5.2 5.0 6.4

6.1 9.7 11.5 10.8 15.3 5.2 5.0 6.3

or the second orthird born ofasetoftriplets, andso

forth. Births with an interval of O months are

excluded from the computation of mean intervals.

Because ofcoding problems involving births inplural

deliveries in 1970, information on births with an

interval of O months for that year are not available

separately, but are included with births having an

interval ofl-11 months.

Residence cla~lcation

All data included in this report are categorized by

place of residence. Births to U.S. residents occurring

outside this country are not reallocated to the United

States and births to nonresidents of the United States

are excluded from tabulations by place of residence.

Data shown in this report refer only to births

occurring within areas reporting dates of last live

birth and last fetal death to residents of these areas.

In tables showing intervals cross-classified with educational attainment of mother or period of gestation,

the data are limited to births occurring in areas

reporting both items to residents of these areas.

Race classii3cation

In all cases, race refers to the child’s race. Because

the race of the mother and child are identical for

most btiths, for ease and clarity in writing this report,

the racial identification given to the mother is that of

the child. Thus the term “white mothers” actually

refers to white births. The category “white” comprises births reported as white, Mexican, Puerto

Rican, and Cuban.

Sample size

For the years 1970-71, birth statistics are based

on a 50-percent sample of birth certitlcates. Information for the years 1972-77 are based on 100 percent

of birth certificates from States participating in the

Cooperative Health Statistics System (CHSS) and on a

50-percent sample of births from all other States.

States providing data through CHSS in 1972-77 are

shown in table III.

Standardization of mean interval since last live birth

The direct method of standardization was used to

eliminate the effect of maternal age changes within

each birth order between 1970 and 1977 on the

differences observed in the mdan intervals during this

period (text figure 2). The 1970 distribution of births

by maternal age within each birth order was used as

the standard population. The following formula was

used to perform the standardization

where

M, = standardized mean interval

Ni = number of births in the ith category of the

standard population

Mi = the mean interval in 1977 for births in the

ith categow in the given population

N = total number of births in the standard population

In a similar manner, the effects of birth-order

changes within each maternal age group between

1970 and 1977 were eliminated (text table F); the

1970 distribution of births by birth order within each

maternal age group served as the standard population.

To eliminate racial differences in maternal age distributions for each birth order (text table G), the

distributions of white births by maternal age within

each bkth order were used as the standard population, and the preceding procedure was followed.

The direct method of standardization was also

used to eliminate the effect of differences in the age

distributions of black and white mothers within

45
Table II 1. Statas with data based on 100 percent of births recaived through the Cooperative Health Statistics System, 1972-77

State 1977 1976 1975 1974 1973 1972

Alabama . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x

Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

Arizona . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Arkansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

California . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Colorado . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Connecticut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dalewara . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DistrictofColumbia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Florida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Georgia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Hawaii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Idaho . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Illinoi s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Indiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Iowa . . . . . . . . . . . . . . . . . . . . . . . .’ . . . . . . . . . . . . . . . . . . . . .

Kansas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Kentucky . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Louisiana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maryland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Massachusetts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Michigan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minnesota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mississippi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Missouri . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Montage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nebraska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nevada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NewHampshire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NawJersey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Mexico . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NewYork(Stataonly) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

North Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

North Dakota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ohio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

Oklahoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x

Oregon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..”... x x

Pennsylvania . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rhode Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x

South Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x

South Dakota .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tennessee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x

Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x

Utah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vermont . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x

Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x

Washington . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

West Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x

Wisconsin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x x x

Wyoming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

x

x

x

x

x

x

x

x

x :,

x

x

x

x

x

x

x

x

x

x x

x x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x x

x x

46
educational levels (using the distribution by age of intervals by educational attainment for these years

white mothers as the standard population) and to (using the 1970 age distribution as the standard

adjust for the changing age distribution of mothers population).

between 1970 and 1977 when comparing mean

●

47
Vital

SERIES 1.

SERIES 2.

SERIES 3.

SERIES 4.

SERIES 10.

SERIES 11.

SERIES 12.

SERIES 13.

iand Health Statistics series descriptions

Programs and Collection Procedures. -Reports describing

the general programs of the National Center for Health

Statistics and its offices and divisions and tha data collection methods usad. They also include definitions and

other material necessary for understanding the data.

Data Evaluation and Methods Raaaarch .–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.

Analytical and Epidemiological 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.

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.

Data From the National 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 the

continuing national household interview survey.

Date From tha National Health Examination Suwey and

the National Health and Nutrition Examination Survey.–

Data from direct examination, testing, and measurement

of national samples of the civilian noninstituti onalized

population provide the basis for (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 finite universe of persons.

Data From the Institutionalized Population Survey s.-Discontinued in 1975. Reports from these surveys are included in Series 13.

Data on Haalth Rasourcas Utilization. –Statistics on the

utilization of health manpower and facilities providing

SERIES 14.

SERIES 15.

SERIES 20.

SE RI ES 21.

SERIES 22.

SERIES 23

For a list of

long-term care, ambulatory care, hospital care, and family

planning services.

Data on Health Resources: Manpower and Facilitias.–

Statistics on the numbers, geographic distribution, and

characteristics of health resources including physicians,

dentists, nurses, other health occupations, hospitals,

nursing homes, and outpatient facilities.

Data From special Suways.–Statistics on health and

health-related topics collected in ‘special surveys that

are not a part of the continuing data systems of the

National Center for Health Statistics.

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.

Data on Natality, Marria@, and Divorce. –Various statistics on natality, marriage, and divorce other than as

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.

Date From tha National Mortality and Natality Surveys.–

Discontinued in 1975. Reports from these sample surveys

based on vital records are included in Series 20 and 21,

respect ivel y.

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 periodic survey of a nationwide

probability sample of ever-married women 15-44 years

of age.

titles of reports published in theaa series, write to:

Scientific and Technical Information Branch

Na~ional Center for Health Statistics ~

Public Health Service

Hyattsville, Md. 20782
U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Public Health Service

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National Center for Health Statistics

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from the Office of Health Researchr Statistics, and Technology

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for a listing of publications in the VITAL AND HEALTH STATISTICS SERIES call 301-436-NCHS