FROM VITAL & HEALTH STATISTICS OF THE NATIONA~ CENTER FOR HEALTH STATISTICS 

o 

o 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE I No. 11 

Pregnant Workers 

Of about 3,034,000 women who had a live 

birth during a 12-month period in 1972-73, an 

estimated 1,260,000 or 41.5 percent worked 

during their pregnancy, according to the National Survey of Family Growth (NSFG). This 

Survey was conducted by the National Center 

for Health Statistics. Such pregnant workers 

comprised about 8.8 percent of the estimated 

14,357,000 ever-married women of reproductive 

age in the labor force at the time. 

For the survey, there were interviews of 

about 9,800 women representing the population 

of women aged 15-44 in households in the conterminous United States who were married, previously married, or single with their own children in the household. This report is based on 

information about women who had a live birth 

in the year before their interview. Because interviewing occurred over an 8-month period in 

1973-74, the years of preintemiew experience 

reported by women include different 12-month 

periods. The aggregated reports of years of preinterview experience refer to an average 12-

month period ending on September 13, 

1973–the interviewing midpoint. For that and 

other reasons, estimates of births reported here 

are not comparable to calendar period estimates 

from the birth registration system. Other aspects 

of sample design and statistical reliability are discussed in the Technical Notes to this report. 

Table 1 shows estimates of the number of 

women who had a live birth in the year before 

the interview, and who worked at some time 

during the nine months before the birth. The 

estimates would have been somewhat higher had 

the sample included all single women instead of 

just those with their own chiIdren in the household. Of the approximately 1,260,000 pregnant 

workers, 83.9 percent were white women, and 

1This report prepared by Gerry E. Hendershot, Ph.D., 

Division of Vital Statistics. 

Sept. 15, 1977 I Public Health Service. Health Resources Administration 

in the United Statesl 

16.1 percent were of “all other”z races. Women 

under 25 years of age were 53.3 percent of the 

total, and women 25 years and over were 46.6 percent of the totaL Among pregnant workers under 

25 years of age, 78.9 percent were white women, 

while among pregnant workers 25 years and 

over, 89.8 percent were white. Among white 

pregnant workers, 49.9 percent were 25 years amd 

over; among pregnant workers of all other races, 

ordy 30.0 percent were 25 years and over. 

Table 2 shows estimates from the Current 

Population Surveys of the numbers of evermarried women employed or seeking employment in March 1972, a date near the midpoint 

of the period during which the pregnancies began. These numbers estimate the population 

potentiality becoming the pregnant workers in 

table 1, although single women with children of 

their own are not included. 

The ratios in table 3 (derived by dividing 

the numbers in table 1 by the numbers in table 

2 and multiplying this by 1,000) are crude indexes of the probability that during a l-year 

period women in the Iabor force wiIl work whiIe 

pregnant. The index was 85 per 1,000 for white 

women as compared with 102 for zdl other 

women. It is highest for women of all other 

races under 25 years of age (370 per 1,000), 

lowest for women of all other races who are 25 

years of age and over (38 per 1,000), and averages 88 per 1,000 for the total population of 

ever-married, reproductive-age women in the labor force. 

2The term “all other” refers to the combined gTouping of all races other than white. 

3 Bueau of Labor Statistics: Marital and Family Characteristics of Workers, March 1972, Special Labor Force 

Report 153. Washington. U.S. Government Printing Office, 1973. This publication provides appropriately classified data nearest in time to the estimated midpoint of 

the period during which the women who are subjects of 

this report became pregnant. 
. . 

,. 

2 dvancedata 

Table 4 shows estimates of the number of 

women in the sampled population who had a 

live birth in the year before their interview. 

Table 5 shows ratios of pregnant workers (from 

table 1) to Women Who had a live birth in the 

year before their interview (from table 4). The 

ratios are approximations to proportions of recently confined women who worked during 

their - pregnancy. The proportion is highest 

among women of all other races in the younger 

age category (48.5 percent), lowest among white 

Table 1. Number and percent distributions of woman 1544 yaars 

of age who worked during a pregnancy ending in live birth 

during a 12-month period in 1972-73 by color and age: United 

States 

I Color 

Age 

Total White All 

other 

Number of women 

1544 years .. ....... , , 

15-24 years ........ ......


2544 years .............. Mm


Percent distribution by color 

15-44 years ......... 

15-24 years.., ........... 

2544 years,., ........... R&H% 

Percent distribution by age 

15-44 years ......... 

15-24 years ..............


25J14 years .............. E m


Table 2. Number of ever-married women 1644 years of age who 

were in the labor force in March 1972, by color and age: 

United States 

I Color 

1644 years, ........ \ 14,357,000 \ 112,370,000 I 1,987,000 

16-24 years .............. 3,265,000 II2,881,000 I 384,000 

25-44years .. ............ I11,092,000 9,489,000 1,603,000 

Source: Bureau of Labor Statistics, Marital and Family Characteristics of Workers, March 1972, Special Labor Force Report 

153. Washington, U.S. Government Printing Office, 1973. 

women in the older age category (36.5 percent), 

and averages 41.5 percent for the totai population of recently confined women, 

A detailed analysis of these and related data, 

entitled “Patterns of Employment Before and 

A“fter Childbirth,” is being prepared for publication in Vital and Health Statistics, Series 23. For 

an earlier report based on a sample of legitimate 

live births, see “Employment During Pregnancy: 

Legitimate Live Births, United States, 1963,” 

Vital and Health Statistics, Series 22, No. 7. 

Table 3. Number of women 1544 years of age who worked during a pregnancy ending in live birth during a 12-m,onth period 

in 1972-73, per 1,000 women ~n the labor force in March 

1972, by color and age: Unitad Statas 

‘ge k-n+hnr 

15-44 years ......... I 8811 85 / 102 

15-24 years ...... ........ 206 184 370 

25-44 years .............. 53 56 38 

0 

Table 4. Number of women 1544 years of age who had a live 

birth during a 12-month period in 1972-73, by color and age: 

Unitad States 

1 5=$4 years ......... I 3,034,000 II 2,582,000 I 452,000 

15-24 years .............. 

I 

1,432,000 293,000

I 

1,139,000 

2544 years .............. 1,602,000 1,443,000 I 159,000 

Table 5. Number of women 1544 yaars of age who worked during a pregnancy ending in live birth during a 12-month period in 1972-73, per 1,000 women who had a live birth in tha 

same period, by color and age: United States 

Color 

Age All Total White other 

1544 years ... ...... 

15-24 years ..... ......... 

25J14 years ............ .. H%=’ 
...........

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

.........

........

.........

.........

......

..........

.........

.........

.........

......

......

......

....

....

dwmedaa 3 

TECHNICAL NOTES 

DESIGN OF THE SURVEY. The National Survey of FamiIy Growth (NSFG) is designed to 

provide data on fertility, famiIy planning, and 

related aspects of maternal and chiId health. 

Field work for Cycle I was done by the National 

Opinion Research Center in 1973 and early 

1974 with September 13, 1973 as the midpoint 

of the interviewing. 

A multistage probability sample of women 

in the noninstitutional population of the conterminous United States was used. Approximately 33,000 households were screened to 

identify the sample of women eligibIe for the 

NSFG, i.e., women aged 15 to 44 years, inclusive, who were currently married, previously 

married, or never married but had biologicallyrelated children presently living in the househoId. In households with more than one eligible 

woman, a random procedure was used to select 

only one to be interviewed. 

Interviews were completed for 5,864 white 

women and for 3,933 women of other races. A 

detailed description of the sampIe design will be 

presented in a forthcoming report, “Sample Design, Estimation Procedures and Variance Estimation for Cycle I of the National Survey of 

Family Growth.” 

RELIABILITY OF ESTIMATES. Since the statistics m-esented in this report are based on a 

samplej they may differ f~om the figures that 

would have been obtained from a compIete census. This difference, referred to as sampling error, is measured by a statistic calIed the standard 

error of estimate. Approximate standard errors 

for estimated numbers from this survey are 

shown in table I. 

The chances are about 68 out of 100 that an 

estimate from the sample would differ from a 

complete census by, less than the standard error. 

The chances are about 95 out of 100 that the 

differences between the sample estimate and a 

complete count would be less than twice the 

standard error. 

Table 1. Approximate standard error for estimated numbers for 

total or white women and black women: 1973 National 

Survey of Family Growth 

Total and white 

Size of Standard 

est imate error 

25,000 ............. 6,000 

!50,000 . 9,000 

100,000 . 13,000 

150,000 . . 16,000 

250,000 . 20,000 

350,000, . 24,000 

500,000 . 28,000 

750,000 . 35,000 

1,000,000 . 40,000 

Black 

Size of Standard 

estimate error 

50,000 . . 15,000


100,000 . 21,000


200,000 . 30,000


500,000 . 47,000


1,000,000 . 67,000


2,000,000 . 95,000


5,000,000 . 151,000


10,000,000 . 216,000


20,000,000 . 311.000


DEFINITION OF TERMS 

Age. –Age is classified by the age of the respondent at her last birthday before the date of 

interview. 

CoJor.–C1assification by color of the woman 

interviewed, based on interviewer observation, 

was reported as white or other. “All other” refers to the combined grouping of all races other 

than white. 

Labor Force Status. –A woman is categorized as being in the labor force if she was working full-time or part-time, had a job but was not at 

work because of temporary illness, vacation, or a 

strike, or if she was unemployed, laid-off, or looking for work. In this report ever-married women 

are included in the labor force estimates; other 

estimates include single women with children. 

Work During Pregnancy. –Women are classified as having worked during pregnancy if they 

had a live birth in the year before the interview, 

and reported that they worked within the nine 

months before the birth. 

Live Births. –A live birth is a fetus that gives 

signs of life after birth, regardless of the Iength 

of gestation. Since this report focuses on women 

having a live birth in a specified period, rather 

than upon the births themselves, it does not alIOW for plural births, and is not, therefore, comparable to reports of births from the birth regis­

@ 
. ,: 

4 ackncedata 

o 

tration system. Because of the sample design, over an 8-month period, the years of preinterthis report also does not include births in Alaska view experience reported by women differ, and 

or Hawaii. Nor does it include women under 15 the aggregated experience is not directly comnor over 44 years of age. Finally, the period for parable to any calendar period for which data 

which births were reported is the 12 months be- from the birth re~istration svstem might be re­ “ d . fore the interview. S;nce interviewing took place ported. 

Previous Issues of Advance Data From Vital and Health Statistics 

No. 10.	 Expected Size of Complete Family Among No. 8. Total Serum Cholesterol Level of Chfldren 

Currently Married Women 15-44 Years of Age 4-17 Years of Age in the United States in 

in the United States in 1973 (Issued: August 1971-74 (Iss.ued:July 11, 1977) 

12, 1977) No. 7. Total Serum Cholesterol Level of Adults 

18-74 Years of Age in the United States in 

No. 9. Wanted and Unwanted Births Reported by 1971-74 (Issued: May 25, 1977) 

Mothers 15-44 Years of Age in the United No. 6. Dietary Intake of Persons 1-74 Years of Age in 

States in 1973 (Issued: August 10, 1977) the United States (Issued: March 30, 1977) 

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