FROM VITAL & HEALTH STATISTICS OF THE NATIONAL CENTER FOR HEAL 7H STATISTICS 

U.S. DEPARTMENT OF HEALTH, . Public Health Serwce


EDUCATION, ANI3 WELFARE Office of Health Research, Statistics, and Technology Number 55 � January 24, 1980


Reproductive Impairments Among Currently Married Couples: 

United States, 1976’ 

INTRODUCTION Figura 1. PERCENT OF ALL CURRENTLY MARRIED COUPLES WITH 

This report presents preliminary estimates of 

fecundity impairments-that is, involuntary 

conditions that make it difficult or impossible to 

have additional children–among currently married couples in the United States in 1976. These 

are the latest national estimates of fecundity impairments and the first since those reported 

from the 1960 Growth of American Families 

Study.2 The data are based on Cycle H of tie 

National Survey of Family Growth (NSFG) 

conducted in 1976 by the National Center for 

Health Statistics. 

In 1976 about 6.9 million couples, or 25 

percent of aIl married couples with the wife of 

childbearing age, had fecundity impairments 

(figure 1). Most of these couples had one chiId 

or more and did not want additional children 

(figure 2). A substantial minority of couples 

with impaired fecundit y—about 2.7 miIIion— 

wanted to have a baby or another baby. About 

848,000 of these couples were childless and 

688,000 had only one child. In alI, couples 

WIFE 15-44 YEARS OF AGE, BY FECUNDITY STATUS: UNITED 

STATES, 1976 

Impaired 

fecundity ‘1vely

Figure 2 PERCENT OF ALL COUPLES WHO HAVE IMPAIRED 

FECUNDITY AND ARE AT GIVEN PARITIES: UNITED 

STATES, 1976 

with impaired fecundity who wanted to have a 

baby or another baby made up about 10 percent 

of the married couples with the wife of childbearing age. 

Statistics on couples with fecundity impairments may be of interest in determining the degree of need for appropriate medical services, in 

assessing the demand for adoption, and in deterlThis report was prepared by William D. Mosher, 

Ph. D., Division of Vital Statistics. 

2 Whelpton, P. K., Campbell, A. A., and Patterson, 0 1 2 3 4 or more 

J. E.: Fertility and Family Plannings% the United States. PARITY {number of children ever born] 

Princeton, N.J. Princeton University Press, cl} 1966, Chap- ,lt,.l,:th nonmmr,qm, ,WIC. long mrwwl. ml mhlm,md LW,!.x. 

ter 4. 
mining the potential effects of fecundity impairments on birth rates. 

The NSFG is based on personal interviews 

with a multistage area probability sample of 

women 15-44 years of age in the household 

population of the conterminous United States. 

Women were eligible for inclusion in the sample 

if they were currently married, previously married, or were never married but had offspring 

presently living in the household. 

The interview focused on the respondents’ 

marital and pregnancy histories, their use of contraception and the planning status of each pregnancy, their use of maternal care and family 

pka.rming services, fecundity impairments, and a 

wide range of social and economic characteristics. Between January and September of 1976, 

3,009 black women and 5,602 women of other 

races were interviewed. Because the estimates of 

statistics in this report are based on a sample, 

they are subject to sampling variability. Further 

discussion of the survey design, definition of 

terms, and sampling variability can be found in 

the Technical Notes. 

Statistics in this report refer to women who 

were currently married at the time of the survey. 

Characteristics reported, such as age, race, number of years since first marriage, and parity 

(number of children ever born), all refer to the 

wife. Fecundity impairments were reported in 

response to questions on whether respondent 

couples had trouble having children. 

CLASSIFICATION BY 

FECUNDITY STATUS 

For this report, fecundity is a characteristic 

that was measured for all currently married 

couples by a series of questions. All currently 

married couples were classified into one of five 

categories of fecundity status: contraceptively 

sterile, noncontraceptively sterile, long interval, 

sub fecund, or fecund. 

Data on fecundity impairments were obtained by asking respondents whether it was 

possible or impossible, or difficult or not difficult, for them to have a baby or another baby. 

If the respondent said it was difficult or impossible, she was asked why. With a few exceptions 

(explained below), respondents who said that it 

was impossible for them to have a baby or 

another baby were classified as sterile, and those 

who said it was difficult were classified subfe- @

cund. The first question on fecundity impairments was the following: 

“It is physically impossible for some couples to have children. As far as you know, is 

it possible or impossible for you and your 

husband to conceive a(nother) baby, that is, 

to get pregnant (again)?” 

Respondents who replied that it was impossible 

for them to have a baby or another baby were 

asked: 

“What is the reason you are unable to have 

a(nother) baby?” 

If the response was that they were sterile because of a surgical procedure, they were then 

asked: 

“What kind of operation was it?”


“Was one reason for the operation because


you had all the children you wanted?””


Contraceptively Sterile 

This category consisted of women or their 

current husbands who had sterilizing operations 9 

at least partly because they had all the children 

they wanted. In 1976, 18.6 percent of the couples in which the wife was 15-44 years of age 

were contraceptively sterile. (This percent differs slightly from a preliminary estimate published in Advance Data Number 36, because of 

revisions made in the data. See “Definition of 

Terms.”) For this report, these couples are not 

classified as having fecundity impairments because they have ended their fecundity voluntarily–that is, as a method of family limitation 

(table 1 and figure 1). 

Noncontraceptively Sterile 

Of those couples with fecundity impairments, the noncontraceptively sterile was the 

largest group. Eleven percent of the currently 

married couples in 1976, or about 3.0 million, 

were noncontraceptively sterile (table 1 and 

figure 1). These couples knew of specific reasons 

why they were sterile. Noncontraceptively 

sterile women replied to the above questions 

that it was impossible for them to have a baby . 
....................................

achme&a3 

o Table 1. Number of all currently married	 womenl 15-44 years of age and percent distribution by fecundity status, according to 

se Iected characteristics: United States, 1976 

Number of COntra- Selected 

characteristic women in Tota I Fecund2 cept ively 

thousands sterile Subfecu nd 

w 

— 

Aga Percent distribution

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

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

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

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

25-34 years .... ................... 

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

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

35-44 years ....................... 

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

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

Parity 

o ...................................... 

1 .. 

2 ..... ................................. 

3	 ................. ..................... 

4 or more ............. ............. 

� Years since wife’s 

first marriage 

Less than 5 years ............... 

5-9 years ........................... 

10-14 years ....................... 

15 years or more. ........ ..... 

Hispanic origin3 

Hispanic . ....... ................... 

Other ............................... 

27,488 100.0 56.1 18.6 

6,020 100.0 85.3 3.5 

1,043 100.0 90.1 *0.8 

4,977 100.0 84.3 4.0 

12,179 100.0 58.7 19.1 

6,443 100.0 68.7 12.5 

5,736 100.0 47.5 26.5 

9,288 100.0 33.8 27.7 

4,814 100.0 36.3 28.9 

4,474 100.0 31.2 26.4 

5,235 100.0 73.0 *1.5 

5,571 100.0 70.9 3.8 

7,638 100.0 55.1 23.3 

4,744 100.0 43.2 30.7 

4,300 100.0 32.3 36.6 

7,039 100.0 86.5 1.8 

6,389 100.0 66.7 13.7 

4,972 100.0 43.2 28.3 

8,750 100.0 31.8 30.2 

1,699 100.0 63.5 10.7 

25,726 100.0 55.6 19.1 

25.3 11.0 3.9 10.4 

1

11.3 *0.6 *0.8 9.8 

9.1 *2.2 *0.I 8.8 

11.7 7.3 *1.O 10.0 

22.2 8.1 2.6 11.5 

18.8 5.4 2.3 11.1 

26.1 11.1 2.9 12.0 

38.5 21.5 7.7 9.3 

34.9 18.8 6.2 9.9 

42.4 24.5 9.3 8.7 

25.5 7.8 5.0 12.7 

25.2 5.9 4.1 15.3 

21.5 9.7 2.6 9.2 

26.1 15.5 3.3 7.3 

31.0 18.8 5.5 5.5 

11.7 2.0 *0.8 9.0 

19.5 3.8 2.1 13.6 

28.6 13.4 4.8 10.4 

38.0 21.8 7.2 9.0 

25.7 8.7 4.1 13.0 

25.3 11.2 3.9 10.2 

lIncIudes races other than white and black. 

2Fecund k used in a different my in this report than in previous reports. See “Definition of Terms.”


3Women of ~~panic origin are included in the figwes for ~~~te and black ~ornen if they were identified as such by the interviewer.


or another baby because (1) the wife or husband sterile by type of operation and-on those who 

had a sterilizing operation (such as a hysterec- intend to have sterilizing operations. 

tomy) that was not done because they had all the 

children they wanted, but for health reasons; or Long Interval (2) that it was impossible for her to have a baby


or another baby because of accident, illness, or This category consists of currently married


some other reason. couples who, during the 3 years of continuous


A future report in Series 23 of Vital and marriage before the interview, did not use conHealth Statistic; will focus on the surgically traception and did not have a pregnancy. Many 

@ 
4 &ncedata 

of these couples are sterile, but some might conceive in the future.3 In 1976, 1.1 million, or 3.9 

percent, of currently married couples were 

classified as having a long interval (table 1 and 

figure 1). 

Subfecund 

For women in this category, it may be possible for them to conceive and/or carry a pregnancy to term, but there are specific difficulties 

in doing so. Most women classified subfecund 

responded affirmatively to the following 

question: 

“Some people are able to have a(nother) 

baby, but they have difficulty getting pregnant or holding onto the baby. As far as you 

know, is there any problem or difficulty for 

you and your husband to conceive or deliver 

a(nother) baby?” 

Women who answered this question affirmatively were then asked the following question: 

“What is the reason it would be difficult for 

you to have a(nother) baby?” 

An estimated 2.9 million couples, or about 

10.4 percent, were classified as subfecund in 

1976 (table 1 and figure 1). Of the subfecund 

couples, an estimated 908,000 were aware of a 

“physical difficulty getting pregnant,” while an 

estimated 638,000 women had difficulty 

carrying the pregnancy a full 9 months. 

All Fecundity Impairments 

This category includes noncontraceptively 

sterile couples, those with long intervals, and 

subfecund couples. In ,1976, 25.3 percent, or 

6,954,000 couples, were classified, as having a 

fecundity impairment. As stated previously, 

this category does not include couples who have 

used a sterilizing operation as a method of 

family limitation. Those couples are called “contraceptively sterile. ” 

3Potter, R. G. and Parker, M. P.: Predicting the time 

required to conceive. Populatbn .StucJies.18(1) :99-116, 

July, 1964. 

Fecund 

In this report, fecund means that there was 

no evidence as of the date of the interview that 

the couple had a problem in conceiving or delivering a baby. These women reported no impairments and stated that it was possible for them to 

have a baby, that they did not have any difficulty conceiving or carrying to term, and they 

did not have a 3-year (or longer) interval of nonuse of contraception without pregnancy immediately before the interview. About 15.4 million, 

or 56.1 percent, of the currently married 

couples were classified as fecund in 1976. As explained in the “Definition of Terms,” this definition differs from the use of the term fecund in 

some other reports where the subfecund and 

long-interval couples, for whom it may stiH be 

possible to have children or additional children, 

were not classified separately. 

The passage of time, nonuse of contraception, or an attempt to have children increase the 

likelihood that couples will discover fecundity 

impairments. (For example, couples who have 

ended their fecundity by contraceptive sterilization or who have always used contraception 

without a pregnancy occurring may have undiagnosed impairment; that would prevent, or make 

difficult, their having children or additional 

children if they later decided they wanted 

m“ore. ) Some effects of the passage of time and 

attempts to have children are indicated by age, 

parity, and number of years since the wife’s first 

marriage (tables 1-3 ). 

FINDINGS 

Table 4 distinguishes between fecundity impairments and the desire for children or additional children by showing the number and percent of women in each fecundity status-parity 

category who would like or intend to have a 

baby or another baby in the future. 

A majority of couples with fecundity impairments would not like, or do not intend, to 

have additional children. But a substantial 

minority did express a desire to have a baby or 

another baby—3 9.3 percent of wives with impaired fecundity (an estimated 2.7 million 

women) said they would like to have a baby 

or another baby. This was 9.9 percent of the 

27,488,000 wives 15-44 years of age in 1976. 
aduancedata 5 

� Table 2. Number of currently married white women 15-44 years of age and percent distribution by fecundity status, according 

to selected characteristics: Unitad States, 1976 

Selected Jumber of 

NOmen in Tota I Facundl characteristic 

thousends 

— 

Age

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

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

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

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

25-34 years ....................... 

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

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

35-44 years .................. ..... 

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

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

parity 

o ...................................... 

1 ................. ..... ................ 

2 ...................................... 

3 ......... ....... ................... ... 

4 or more ................. ....... .. 

Years since wife’s 

first marriage 

Less than 5 years ............... 

5-9 years .............. ...... ....... 

10-14 years ....................... 

15 years or nmre ............... 

24,795 100.0 56.1 

5,412 100.0 86.5 

918 100.0 90.7 

4,493 100.0 85.6 

10,883 100.0 58.1 

5,806 100.0 68.2 

5,187 100.0 46.7 

8,390 100.0 33.8 

4,339 100.0 36.2 

4,051 100.0 31.3 

4,874 100.0 73.9 

4,922 100.0 71.5 

6,939 100.0 54.6 

4,330 100.0 41.8 

3,729 100.0 31.6 

6,253 100.0 87.2 

5,740 100.0 67.4 

4,512 100.0 42.6 

8,048 100.0 31.7 

1 Fecund i5 wed in ~ different ~wy in this report than in pP3\iOUS 

However, a majority of childless couples 

with fecundity impairments (63.5 percent, or 

about 848,000) would like to have a baby, and 

49.0 percent (688,000) of couples with fecundity impairments who have one child (panty 

one) would like to have another (table A). The 

percent of couples ..mnting a baby or another 

baby declined with parity in each category of 

fecundity impairments. The one exception, in 

the long interval category, is not statistically 

significant. 

Since noncontraceptively sterile couples are 

not able to bear a child or another child, these 

wives were asked: “Do you intend to adopt any 

children?” Overall, 12.2 percent responded 

affirmatively, including 39.1 percent of noncontraceptively sterile wives at parity zero, 14.8 

Impaired fecundity 

COntraceptively All Noncontra- Long 

sterile impaired ceptivel y interval Subfecund 

sterile 

Percent distribution 

19.3 24.6 11.0 3.5 10.1 

3.5 10.0 *0.6 *0.6 8.9 

‘0.8 8.5 *0.O *0. I 8.4 

4.0 10.4 0.7 ‘0.7 9.0 

20.1 21.8 8.1 2.3 11.4 

13.1 18.6 5.2 2.0 11.3 

27.9 25.4 11.4 2.6 11.5 

28.5 37.7 2? .5 7.0 9.2 

30.0 33.9 18.2 5.7 10.0 

26.9 41.8 25.0 8.5 8.3 

*1.5 24.6 7.7 4.9 12.0 

4.2 24.3 5.7 3.5 15.0 

24.9 20.5 9.5 2.1 8.9 

31.8 26.4 15.7 3.3 7.4 

37.5 30.9 19.7 4.7 6.5 

1.8 11.1 2.0 *0.7 8.4 

14.6 18.0 3.4 1.5 13.1 

29.4 27.9 13.3 4.4 10.2 

30.7 37.6 22.0 6.5 9.0 

WpOIIS. see “Definition ‘f Terms.” 

percent at parity one, 7.0 percent at parity two, 

and 6.5 percent at parity three or more. 

Sub fecund wives were asked: “In the past 3 

years, have you talked with a doctor or other 

trained person about increasing your chances of 

having a baby?” About 1 in 4, or 26.2 percent, 

responded affirmatively; this represents about 

749,000 women. This percent also declined with 

parity, from 50.7 percent of subfecund wives at 

parity zero to 34.9 percent at parity one, 11.1 

percent at parity two, and 5.5 percent at parity 

three or more. 

Calculations based on table 1 (but not 

shown here) showed that coupIes with impaired 

fecundity were older than fecund couples. Fecund wives, of whom about 38 percent w-ere 

30-44 years of age, were the youngest of the 
...................................

6 dwmdata 

Table 3. Number of currently married black women 15-44 years of age and percent distribution by fecundity status, according to 

selected character ist ics: United States, 1976 0 

Impaired fecundity 

Selected 

characteristic 

Age 

All ages., .... ............. 

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

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

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

25-34 years ........................ 

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

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

35-44 years ....................... 

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

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

Parity 

o ...................................... 1 . .. 

2 ............................. ......... 

3 ...................................... 

4 or more ........................ . 

Years since wife’s 

first marriage 

Less than 5 years .............. 

5-9 years ............. .............. 

10-14 years ....................... 

15 years or more ............... 

MI mber of Contra-


women in Total Fecundl captively Noncontra­


thousands eterile All Long


impaired ceptivel y interval Subfecund 

sterile 

Percant distribution 

2,169 12.6 

509 100.0 74.8 * 4.0 

99 100.0 82.6 *1.2 

410 100.0 72.9 *4.7 

912 100.0 64.9 9.6 

484 100.0 72.8 6.8 

428 100.0 56.0 12.8 

749 100.0 32.1 22.2 

368 100.0 36.7 22.0 

381 100.0 27.6 22.4 

242 100.0 57.4 ‘0.8 

526 100.0 66.0 *0.7 

565 100.0 63.3 9.1 

312 100.0 54.7 20.1 

524 100.0 37.8 29.4 

585 100.0 81.6 *2.6 

503 100.0 62.5 7.0 

368 100.0 48.5 15.4 

627 100.0 32.5 25.1 

31.4 11.1 

21.2 *1.5 

‘1 6.2 *2.3 

22.4 *1.3 

25.5 8.5 

20.4 8.4 

31.2 8.6 

45.7 20.7 

41.3 19.8 

50.0 21.5 

41.8 14.8 

33.3 7.4 

27.6 10.1 

25.2 12.3 

32.7 13.4 

15.8 2.4 

30.5 6.8 

36.1 17.1 

42.4 17.5 

8.2 12.2 

*4.O 15.7 

*0.O 13.9 

*5.O 16.2 

5.6 11.4 

*4.2 7.8 

*7,1 15.4 

14.2 10.8 

11.8 9.7 

16.5 12.0 

*9.7 17.2 

8.5 17.4 

6.4 11.2 

*5.O *7.9 

10.9 8.4 

*2.1 11.3 

7.9 15.8 

*4.9 14.1 

15.4 9.5 

1 Fecund is used in a different way in this report in previous reports. See “Definition of Terms. ” 

fecundity status categories. Subfecund wives, 

with about 54 percent at 30-44 years of age, 

were somewhat older. Noncontraceptively sterile 

wives, of whom 87 percent were 30-44 years of 

age, were the oldest of the fecundity status 

groups. 

Among those with fecundity impairments, 

the distribution of the types of impairments 

changes over time. For example, for those 

married less than 5 years before the interview, 

sub fecund couples accounted for about threefourths of all couples with fecundity impairments (table 1). However, for those married 15 

years or more subfecundity accounted for about 

one-fourth. These observations suggest that 

some couples may discover, as well as develop, 

impairments as they grow older, thereby moving 

from subfecund to noncontraceptively sterile. 

TabIes 1, 2, and 3 show the distribution of 

currently married couples of reproductive age 

in 1976, by fecundity status and selected characteristics of the wife. The prevzdence of fecundity impairments increases with the age of 

the wife. Table 1 shows that for couples of all 

races the percent with impairments increased 

from 11.7 percent at ages 20-24 years to 42.4 

percent at ages 40-44. The percent fecund decreased from 84.3 percent to 31.2 percent at 

the same ages, but much of that decrease was 

due to contraceptive sterility, which is not ckssified as a fecundity impairment. 

The estimated number of couples in which 

the wife had no children (was of zero parity) 

and a fecundity impairment was about 

1,335,000, or 4.9 percent of alI coupIes in 1976. 

Of these, about 408,000, or 1.5 percent of all 
................................

ackincedata 7 

Table 4. Number and percent of currently married women 1544 

years of age with fecundity impairments who intend or would 

like to have a future baby, by fecundity status and parity: 

United States, 1976 

Parity 

All parities ........ 

o ................................. 1 . 2 ................................. 

3 ................................. 

4 or more..................... 

All parities ......... 

o .................................. 1 .................................. 

2 .................................. 

3 .................................. 

4 or more ...................... 

Number who would like or intend a 

future baby in thousands 

848 238 118 490 

688 176 +46 468 

506 324 *37 145 

347 264 *12 *71 

343 267 *27 *4O 

Percent who would like or 

intend a future baby 

39.3 

63.5 58.4 45.2 73.7 

49.0 53.4 20.3 55.1 

30.8 43.8 18.8 20.6 

28.0 35.9 7.8 20.5 

25.7 33.0 11.4 16.8 

NOTE: Numbers may not add to the totals due to rounding. 

Denominators of these percents were calculated from the numbers and percents in table 1. 

couples, were noncontraceptively sterile and 

had-no children. 

The fecundity status of couples was associated with the number of years between the 

wife’s first marriage and the interview date 

(table 1). For wives married less than 5 years 

before the interview date, 11.7 percent of the 

couples had fecundity impairments; this percent increased about 10 percentage points for 

each 5 years to 38.0 percent for women first 

married 15 years or more before the interview. 

For wives of Hispanic origin, 25.7 percent 

reported fecundity impairments compared with 

25.3 percent for other wives; this difference is 

not statistically significant. Noncontraceptive 

sterility was reported by 8.7 percent of Hispanic 

wives compared with 11.2 percent of other 

wives, not a statistically significant difference. 

Tables 2 and 3 show data for white coupIes 

and black couples, respectively. Among black 

couples, 31.4 percent reported fecundity impair­ � 

ments compared with 24.6 percent of white 

couples. However, most of this 6.8 percentage 

point difference is due to the larger percent of 

black couples with long intervals (8.2 percent 

compared with 3.5 percent of white coupIes). 

The rest of the difference is due to a slightly 

(but not significantly) higher percent of black 

couples classified as subfecund (12.2 percent 

compared with 10.1 percent). The percent of 

couples reporting noncontraceptive sterility was 

not significantly different by race (11.1 percent 

of black couples and 11.0 percent of white 

couples). 

The percent of white and black couples who 

were noncontraceptively sterile was not significantly different in any of the 1O-year age groups 

(tabIes 2 and 3). (To reduce sampling variability, 

the comparisons by race are discussed here in 

10-year age groups. ) The main differences between black and white couples are in the subfecund and long interval categories. At 15-24 years 

of age, the principal difference is that black 

couples have a higher percent subfecund than 

white couples do—1 5.7 percent compared with 

8.9 percent. In the age group 35-44 years, the 

percent of black couples with long intervals was 

14.2 compared with only 7.0 percent of white 

couples. 

‘Finally, the percent of wives reporting fecundity impairments was 11.2 percentage Points 

higher -for ~lack coursles than For whit: c&PIes . . 

at 15-24 years of age, and 8.0 percentage points 

higher at 35-44 years of age, but only 3.7 percentage points higher at 25-34 years of age. This 

difference at ages 25-34 years was almost entirely due to a higher percent of black couples 

with long intervals. 

The percent of all currently married couples 

who had no children (were of parity zero) and 

were noncontraceptively sterile was not significantly different by race. In 1976, the estimated 

number was about 375,000, or about 1.5 percent, of the 24,795,000 white couples, and 

about 36,000, or approximately 1.7 percent, of 

the 2,169,000 black couples. 

The percent of white and black couples who 

reported a fecundity impairment and had no 

children (parity zero) was not significantly different-4.8 percent of white couples and 4.7 

percent of black couples. Thus bIack couples 

were no more likeIy than white couples to be 

childless and have fecundity impairments. 
8 advancedakl 

The percent of couples with one or more 

children who were noncontraceptively sterile 

was slightly (but not significant,Iy) lower for 

black couples than for white couples–l 1.8 percent of the 19,920,000 white couples with one 

child or more compared with 10.6 percent of 

the 1,927,000 black couples with one child or 

more. 

Black wives 15-44 years of age had a larger 

average number of children than white wives in 

1976. For example, 11 percent of black couples 

had no children (were at panty zero), compared 

with 20 percent of white couples; and 24 percent had 4 or more children compared with 15 

percent of white couples. Further, the percent 

of couples at parity one or more with impairments was higher for black couples than for 

white couples–30.2 percent of the 1,927,000 

black couples with one child or more compared 

with 24.7 percent of the 19,920,000 white 

couples with one child or more. Thus the higher 

TECHNICAL 

percent of zdl black couples with impairments 

(3 1.4 percent compared with 24.6 percent, of o 

white couples) appears to be due to a higher percent of black coupIes with children who are subfecund or have long intervals. 

The prevalence of impairments was higher 

for black wives than for white wives in each 5-

year interval since the wife’s first marriage, 

although the differences at less than 5 years and 

15 years or more are not statistically significant. 

In each case at least half of the difference was 

due to the long interval and subfecund categories. 

A detailed report on fecundity impairments 

is planned to appear in Series 23 of Vital and 

Health Statistics. That report will present 

findings on the relation of fecundity status to 

other characteristics of couples with special 

emphasis on parity and the desire for additional 

children. 

NOTES 

Cycle II of the National Survey of Family tables III and IV for the black population. ProGrowth (NSFG) was based on interviews with a 

multistage area probability sample of women 15-

44 years of age in the household population of 

the United States. The interviews were conducted between January and September of 

1976. The sampling and estimation procedures 

for Cycle I, conducted in 1973, are described in 

preceding reports based on the NSFG, and 

described in detail in “National Survey of Family 

Growth, Cycle I: Sample Design, Estimation 

Procedures, and Variance Estimation, ” Series 2, 

No. 76, of Vital and Health Statistics. A similar 

report is planned for Cycle II. 

Since the estimates in this report are based 

on a sample of the population rather than on 

the entire population, they are subject to 

sampling error. 

Sampling error, or the extent to which samples may differ by chance from a complete 

count, is measured by a statistic called the standard error of estimate. Approximate standard 

errors for estimated numbers and percents from 

Cycle I are shown in tables I and II for white 

women and women of all races combined and in 

.visionaI estimates of standard errors for Cycle 11 

for white women and women of all races combined can be obtained by multiplying the standard errors for these women from Cycle I by factors of 1.09 for the latter and 1.06 for white 

women. Similarly, provisional estimates of 

standard errors for Cycle 11 for bIack women can 

be obtained by multiplying the standard errors 

for black women from Cycle I by a factor of 1.14. 

Table 1. Approximate standard errors for estimated numbers for 

white women and women of all races combined: 1973 

National Survey of Family Growth 

Relative 

Standard Size of estimate standard error error 

50.000 .............................................. 

1oo,ooo ............................................ 

2oo.ooo ............................................ 

5oo.ooo ............................................ 

1,ooo,ooo ......................................... 

2,000,000 ......................................... 

5,000,000 ......................................... 

10,000,000 ....................................... 

20,000,000 ........................................ 

30.0 15,000 

21.2 21,000 

15.0 30,000 

9.5 47,000 

6.7 67,000 

4.8 95,000 

3.0 151,000 

2.2 216,000 

1.5 i 1,000 

0 
...........

admcdaa9 

●Table 11. Approximate standard errors for estimated percents ex- standard error. The reIative standard error is the 

pressed in percentage points for whita women and women of ratio of the standard error to the statistic being 

all races combined: 1973 National Survey of Family Growth estimated. In this report, numbers and percents 

which have a relative standard error that is more 

Est imat ed percent than 25 percent of the estimate itself are conBase of percent 2or IT5or 10 or’ 20 or 30 or 4001 sidered unreliable. They are marked with an 

98 95 90 80 70 60 

50 asterisk to caution the user but may be combined to make other types of comparisons of 

100,000 . 3.0 4.6 6.4 8.5 9.7 10.4 10.6 greater precision. 

1,000,000 ......... 0.9 1.5 2.0 2.7 3.1 3.3 3.3 For Cycle H of the NSFG, missing data 

3,000,000 ......... 0.5 0.8 1.2 1.5 1.8 1.9 1.9 items were not imputed, and percent distribu5,000,000 .... ..... 0.4 0.6 0.9 1.2 1.4 1.5 1.5 tions are based on cases with known data. The 

7,000,000 ......... 

10,000,000 ....... 

0.3 

0.3 

0.5 

0.5 

0.8 

0.6 

1.0 

0.8 

1.2 

1.0 

1.2 

1.0 

1.3 

1.1 fecundity status of about 15,000 women out of 

an estimated 31,847,000 totzd ever-married 

500,000 ............ 1.3 2.1 2.8 3.8 4.3 4.6 4.7 

women (less than 0.1 percent) was not ascerTable I I 1. Approximate standard errors for estimated numbers tained. 

for black women: 1973 National Survey of Family Growth More extensive “Technical Notes” and “Definition of Terms” can be found in any of the earRelative lier NSFG reports–for example, Advance Data 

Size of estimate standard Standard 

error Numbers 36,43, and 45. error 

● 

25.000 ............................ .................. 25.3 6,000 DEFINITION OF TERMS 

50.mo .............. ......................... ....... 17.9 9,000 

1oo,ooo ............................................ 

1 50,000 ................... ......................... 

12.7 

10.3 

13,000 

16,000 Fecundity. –In this report, fecundity is a 

250.000 ....... ........ ............ ................. 8.0 20,000 characteristic of a currently married couple. It 

350.000 ............................................ 

5oo.ooo ......................................... ... 

750.000 ............................................ 

6.8 

5.7 

4.7 

24,000 

28,000 

35,000 

refers to the ability of the couple to reproduce, 

that is, to have Iive-bom children, at the date of 

1 ,ooo,ooo ......................................... 4.0 40,000 the interview. Fecundity wras measured using a 

series of questions. The responses to these quesTable IV. Approximate standard errors for estimated percents ex- tions permit the classification of couples into 5 

pressed in percentage points for biack women: 1973 National categories: contraceptively sterile, noncontraSurvey of Family Growth ceptit’ely sterile, long intend, sub fecund, or 

fecund. 

Estimated percent Fecundity status. –This refers to the cateBase of percent z or 5or 10or 200r gory of fecundity in which a couple is classified. r98 95 90 I 80 Fecundity impairment. –A fecundity impairment, or reproductive impairment, is any 

5,000 ................. 7.9 12.3 17.0 22.6 25.9 27.7 28.3 medical, physical, or behavioral condition that 

10,000 ............... 5.6 8.7 12.0 16.0 18.3 19.6 20.0 damages or diminishes a couple’s ability to have€ 50,000 ............... 2.5 3.9 5.4 7.1 8.2 8.8 8.9€

100,000 ............. 1.8 2.7 3.8 5.1 5.8 6.2 6.3 children. Contraceptive sterilization operations,€

300,000 ............. 1.0 1.6 2.2 2.9 3.3 3.6 3.6 that is, operations done for purposes of contra-€

500,000 ............. 0.8 1.2 1.7 2.3 2.6 2.8 2.8 ception (family limitation) are not classified as 700,000 ............. 0.7 1.0 1.4 1.9 2.2 2.3 2.4 

1,000,000 .......... 0.6 0.9 1.2 1.6 1.8 2.0 2.0 fecundity impairments. The conditions discussed, except for the Iong interval catego~, 

were Iimited to conditions reported by women in 

The chances are about 68 out of 100 that an response to the questions quoted in the text. 

estimate from the sample would differ from a In a survey of women in the childbearing 

complete census by less than the standard error. years, success in measuring fecundity impairThe chances are about 95 out of 100 that the ments depends on the amount of medical infordifferences between the sample✎ 

● 

estimate and a mation respondents have about themsel~~es, on 

complete count would be less than twice the their interest in .laving chiIdren in the future, 
� 

10 

and on the opportunities they have had to 

detect that a problem exists. Nonetheless, most 

respondents do know the answers to the 

questions asked in the NS FG interview: whether 

or not they have had a sterilizing operation, 

accident, illness, or congenital problem; whether 

or not they have been trying to get pregnant and 

have not used contraception for a substantial 

period of time; and whether or not a doctor has 

told them they have medical conditions that 

would make having a(nother) child difficult or 

dangerous. Data of this kind can be grouped into 

categories such as those used in this report, with 

which to make comparisons between population 

groups, and for use in making estimates of 

needed services such as infertility services. 

Fecund.– In this report a couple was classified as fecund if the respondent reported that 

(1) it was possible to have a baby or another 

baby, (2) there was no difficulty having 

a(nother) baby, and (3) the couple had’ used 

contraception sometime in the 3 years before 

the interview or the wife had been pregnant in 

that period of time. This is a more restricted use 

of the term fecund than in previous NS FG reports,4 which used a 2-category classification— 

“sterile” and “fecund.” In those reports, “fecund” (meaning not sterile) included all women 

classified in this report as fecund and subfecund, 

and most of those with long intervals. 

Fecundity may be viewed as a characteristic 

of a couple that ranges from zero to high (or unimpaired). Couples classified as fecund have no 

reported impairments and no 3-year interval of 

nonuse of contraception without conception. As 

shown in the text, the likelihood that a couple 

will be classified as fecund is partly a function of 

the amount of time since the wife’s first marriage, whether and how many times she has 

attempted to have a child, whether contraception has been used, etc. 

Sub~eczmcL–Women (or couples) classified 

as “subfecund” reported that they were not 

sterile but that they had a problem or difficulty 

in conceiving or delivering a(nother) baby for 

some specific reason; or that a pregnancy in the 

future would be so dangerous to the woman, or 

the baby, or both that she would have a sterilizing operation or abortion if another preg4Advanc; Data Numbers 36 and 45. 

nancy occurred. Thus sub fecund couples are not 

sterile, but they have some reason to believe that 0 

their ability to reproduce is diminished or 

impaired. 

Long interual. –Currently married couples 

are classified “long interval” if they have been 

continuously married for 3 years or more 

immediately before the interview, have not used 

contraception, and have not conceived. About 

three-fourths of these women reported that it 

was possible for them to have a baby or another 

baby. Most of the couples with long intervals are 

sterile, but a small proportion might conceive in 

the futures 

Noncontraceptively sterile. —Women were 

classified as “noncontraceptively sterile” if they 

indicated that it was impossible for them to have 

a baby or another baby for some specific reason 

other than family limitation—such as a medically 

necessary operation, or a nonsurgical reason 

such as accident, illness, or natural menopause. 

For a few respondents, the contraceptive intent 

of their sterilizing operation was not ascertained. 

Contraceptively sterile. –Couples classified as 

“contraceptively sterile” are not included among 

those with fecundity impairments because they 

have had a sterilizing operation at least partly as e a method of contraception or family limitation. 

As noted in the text, the number and percent of 

currently married couples classified as contraceptively and noncontraceptively sterile in this 

report differs sIight.ly from numbers and percents given in A duanc.e Data Number 36, because data on sterilizations of married couples in 

which both husband and wife had been surgically sterilized were recoded to give priority to 

the wife’s operation. This procedure provides a 

complete count of surgical sterilizations among 

ever-mamied women. A complete estimate of 

vasectomies cannot be obtained from this survey 

because not all ever-married men are represented. Where both spouses had been sterilized, 

the husband’s sterilization generally occurred 

first and for contraceptive (family limitation) 

reasons; the wife’s operation followed some time 

later for therapeutic reasons. Consequently, 

giving priority to the wife’s operations has lowered somewhat the percent of couples with con5 See reference cited in footnote 3. 
---

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

adwmcaa 11 

traceptive sterilizations compared with the previously published figures. 

Would like (or intend) to have a(nother) 

baby. –Noncontraceptively sterile women were 

asked: “even though it is unlikely or impossible 

for you to have a(nother) baby, would you like 

to have a(nother) baby?” Subfecund women and 

women with long intervals were asked: “Do you 

and your husband intend to have a(nother) 

baby?” It is assumed that these questions ascertain a desire for additional children in reasonably comparable ways. 

Pan”ty. –Parity refers to the number of live 

births the respondent has had. 

Years since ujife’s first marriage. –This refers 

to the number of years between the wife’s first 

marriage and the interview date. 

Marital status. –This report is based only 

upon currently married women. Couples who 

are temporarily separated for reasons other than 

maritaI discord, such as vacation, illness, or 

Armed Forces, are classified as married. 

SYMBOLS 

I Data not available-—-—-—-———–—-—-

I Category not applicable . . . 

Quantity zero--------—------–--–-—-——— -

Quantity more.than O but less than 0.05— 0.0 

Figure does not meet standards of 

* reliability or precision-–-—--–-–————— 

I 

Recent Issues of Advance Data From Vital and Health Statistics 

No. 54. Fats, Cholesterol, and Sodium Intake in the Smoking Practices Among Adults: United 

Diet of Persons 1-74 Years: United States States, 1978 (Issued: September 20, 1979) 

(Issued: December 17, 1979) 

No. 51. Overweight Adults in the United States 

No. 53. Office Vkits Involving X-rays, National Am- (Issued: August 30, 1979) 

bulatory Medical Care Survey: United States, 

1977 (Issued: September 11, 1979) No. 50. Office Visits by Black Patients, National Ambulatory Medical Care Survey: United States, 

No. 52. Changes in Cigarette Smoking and Current 1975-76 (Issued: July 23, 1979) 

A complete list of Advance Data From Vital and Health Statistics is available from the Scientific and Technical 

Information Branch.