C The National Survey of Family Growth: Principal Source of Statistics on Unintended Pregnancy: Supplement to Chapter 2

Kathryn London, Ph.D., Linda Peterson, M.A., and Linda Piccinino, M.P.S.

National Center for Health Statistics

The National Survey of Family Growth (NSFG) is the most comprehensive source of information available on pregnancy and contraceptive use among reproductive-age women (15–44 years) in the United States. The greatest strengths of the NSFG as a source of data on unintended pregnancy are (1) the wealth of information that it contains on pregnancy, contraceptive use, and related topics and (2) the repetition of the questions on unintended pregnancy in each round of the NSFG, permitting analysis of long-term trends. Besides detailed questions on the intendedness of each of a woman's pregnancies, the NSFG collects information on contraceptive use and method choice, infertility, use of family planning services, birth expectations, and marriage and cohabitation. The survey also collects information on other social and demographic characteristics that have been found to influence reproductive behaviors, such as family background, income, education, and labor-force participation.

The NSFG is federally funded and is conducted by the National Center for Health Statistics (NCHS). Surveys have been conducted in 1973, 1976, 1982, and 1988. In 1973 and 1976 the samples were restricted to ever-married women, among whom most childbearing in the country had occurred. In 1982 and 1988, women of all marital statuses were included. In 1990, respondents from the 1988 survey were briefly reinterviewed by telephone. The next round of the NSFG is being conducted in 1995, and with a brief telephone reinterview planned for 1997.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 286
--> C The National Survey of Family Growth: Principal Source of Statistics on Unintended Pregnancy: Supplement to Chapter 2 Kathryn London, Ph.D., Linda Peterson, M.A., and Linda Piccinino, M.P.S. National Center for Health Statistics The National Survey of Family Growth (NSFG) is the most comprehensive source of information available on pregnancy and contraceptive use among reproductive-age women (15–44 years) in the United States. The greatest strengths of the NSFG as a source of data on unintended pregnancy are (1) the wealth of information that it contains on pregnancy, contraceptive use, and related topics and (2) the repetition of the questions on unintended pregnancy in each round of the NSFG, permitting analysis of long-term trends. Besides detailed questions on the intendedness of each of a woman's pregnancies, the NSFG collects information on contraceptive use and method choice, infertility, use of family planning services, birth expectations, and marriage and cohabitation. The survey also collects information on other social and demographic characteristics that have been found to influence reproductive behaviors, such as family background, income, education, and labor-force participation. The NSFG is federally funded and is conducted by the National Center for Health Statistics (NCHS). Surveys have been conducted in 1973, 1976, 1982, and 1988. In 1973 and 1976 the samples were restricted to ever-married women, among whom most childbearing in the country had occurred. In 1982 and 1988, women of all marital statuses were included. In 1990, respondents from the 1988 survey were briefly reinterviewed by telephone. The next round of the NSFG is being conducted in 1995, and with a brief telephone reinterview planned for 1997.

OCR for page 286
--> Definitions and Measurement Issues Since the first NSFG in 1973 (and also in four national fertility surveys that were precursors to the NSFG, conducted in 1955, 1960, 1965, and 1970), married women have been asked whether they and their husbands wanted each of their pregnancies. The questions were extended to unmarried women and their partners in 1982. The series of questions on unintended pregnancy has remained essentially unchanged, preserving the comparability of the data over time and permitting trend analysis. Women's responses to the following questions are used to code pregnancies as intended (wanted) or unintended (mistimed or unwanted): Question C-1. Before you became pregnant …, had you stopped using all methods of birth control? Yes 1 (If the answer is yes, go to question C-2) No 2 (If the answer is no, go to question C-3) Question C-2. Was the reason you had stopped using any methods because you yourself wanted to become pregnant? Yes 1 (go to question C-5) No 2 (go to question C-3) Question C-3. At the time you became pregnant …, did you yourself, actually want to have a(nother) baby at some time? Yes 1 (go to question C-5) No 2 (go to question C-6) Don't know 3 (go to question C-4) Question C-4. It is sometimes difficult to recall these things but, just before that pregnancy began, would you say you probably wanted a(nother) baby at some time or probably not? Probably yes 1 (go to question C-5) Probably no 2 (go to question C-6) Didn't care 3 (go to question C-6) Question C-5. Did you become pregnant sooner than you wanted, later than you wanted, or at about the right time? Sooner 1 Later 2 Right time 3 Didn't care 4

OCR for page 286
--> Question C-6. And what about your partner at the time you became pregnant …, did he want you to have a(nother) baby at some time? Yes 1 (go to question C-7) No 2 (skip out) Don't know 3 (skip out) Question C-7. Did you become pregnant sooner than he wanted, later than he wanted, or at about the right time? Sooner 1 Later 2 Right time 3 Didn't care 4 Pregnancies are classified as "wanted" if the answer to question C-5 was "later" or "right time." Pregnancies for which the answer to question C-5 was "didn't care'' are also commonly classified as "wanted." Pregnancies are classified as "mistimed" if the answer to question C-5 was "sooner." Finally, pregnancies for which the answer to question C-3 was "no" or the answer to question C-4 was "probably no" are classified as "unwanted." Although the NSFG has effectively measured trends in unintended pregnancy, there are some limitations to the kinds of analysis that can be done. First, as with most fertility surveys, the NSFG suffers from underreporting of abortion. An estimated 35 percent of the actual abortions in the 4-year period prior to the 1988 survey were reported in the survey (Jones and Forrest, 1992). Because not all women surveyed report all of the abortions that they have had, most studies of unintendedness have minimized bias by restricting the sample to live births. Many analysts also adjust for underreported abortions by assuming that 100 percent of unreported abortions were unintended pregnancies. A second limitation of the data is that the wantedness questions are misunderstood by some respondents. Teenagers seem particularly vulnerable to misunderstanding, as indicated by the large proportion of recent births to teens that were reported unwanted—22 percent of births to women ages 15–19 in the 5 years before the 1988 interview date (Piccinino, forthcoming). Testing of a follow-up clarifying question in the NCHS Questionnaire Design Research Laboratory found evidence that although some women accurately reported a pregnancy as unwanted (they did not want to get pregnant then or at any time in the future), other women who reported pregnancies as unwanted corrected their answers to say that they had become pregnant sooner than they had wanted, that is, the pregnancy was mistimed, but not unwanted. Two often-mentioned circumstances that apparently led women to mistakenly answer that they "did not want to have a(nother) baby at some time" were (1) the pregnancy occurred much earlier than desired, possibly by many years, and (2) they had no desire

OCR for page 286
--> to have a baby with that particular partner, even though they wanted to have a baby at some time. Third, respondents are asked to classify pregnancies in a fairly rigid way—either they wanted to get pregnant or they did not. Feelings of ambivalence are not measured. Understanding of unintended pregnancy would no doubt be advanced by measuring ambivalence in men's and women's attitudes toward becoming pregnant, the determinants and magnitude of the ambivalence, and its relation to contraceptive practices. Fourth, the role of ineffective contraceptive use has not been well measured. The NSFG consistently finds that most women at risk of unintended pregnancy use contraception, yet a large percentage of births are unintended. Several studies have looked at the planning status of pregnancies to try to better understand the role of contraception in unintended pregnancy. In such studies pregnancies are classified as "planned" or "unplanned" rather than "intended" or ''unintended" (Pratt et al., 1992; Williams and London, 1992). The NSFG collects information on the planning status of every pregnancy, that is, whether the woman was using birth control at the time of conception (question C-1 above) and, if not, whether her purpose was to become pregnant (question C-2 above). Pregnancies are considered unplanned if they were conceived while a woman was using birth control or while she was using no birth control but not because she desired pregnancy. Thus, whereas "unplanned" has been used to emphasize the behavioral aspects of wantedness, "unintended" reflects attitudes toward a pregnancy. From questions C-1 and C-2 listed above, one can classify women's unplanned pregnancies by type, that is, method or user failures versus failures to use contraception at all. Yet further information is needed. From the current questions, one cannot discern whether women who reported using contraception during the month that they became pregnant actually used a method at the time that they conceived. Method users do not necessarily use their method correctly or every time that they have sexual intercourse. The NSFG lacks measures of the extent to which unplanned pregnancies result after the incorrect use of methods, from methods that are faulty themselves, and from failure to use a method at all. NSFG Plans for the Future The revised 1995 NSFG questionnaire may produce better data on unintended pregnancy. Four goals have been identified: (1) to improve abortion reporting (and therefore permit unbiased analysis of all pregnancies, not just live births), (2) to clarify questions on unwanted and mistimed pregnancies, (3) to measure women's ambivalent feelings about becoming pregnant, and (4) to

OCR for page 286
--> improve understanding of unplanned pregnancies through better measures of contraceptive use. Improving Abortion Reporting Two new techniques seek to improve abortion reporting: (1) allowing respondents to record their abortion histories in private via audio computer-assisted self-interviewing (A-CASI), and (2) paying respondents an incentive so that they will participate in the survey (which apparently has the additional benefit of eliciting more honest answers). NCHS and their data collection contractor, Research Triangle Institute (RTI), tested both techniques in the NSFG pretest in 1993 with encouraging results. Using A-CASI, a subset of NSFG pretest respondents listened via headphones to recorded questions asking whether and when they had had abortions. Women typed their answers directly into the computer; the interviewer did not see their answers. Some NSFG pretest respondents received a $20 or a $40 incentive to participate whereas other respondents received no incentive. NSFG pretest results showed that both A-CASI and monetary incentives significantly increased abortion reporting. About 14 percent of respondents who received no incentive and no A-CASI interview reported ever having had an abortion, whereas 30 percent of respondents who received both an incentive and an A-CASI interview reported ever having had an abortion (Research Triangle Institute, 1994). According to an independent estimate, 29 percent of women aged 15–35 in 1992 have had one or more abortions (Baldwin et al., forthcoming). The NSFG pretest sample was small (500 respondents) and not nationally representative, so one must view its findings with some caution. Yet the findings raise the hope that through these new techniques abortion reporting in the 1995 NSFG will improve significantly, and perhaps even approach complete reporting. Clarifying Questions on Unwanted and Mistimed Pregnancies NSFG staff have redesigned some of the questions used to measure unwanted and mistimed pregnancies. First, the 1995 NSFG has added the following preamble stressing the importance of the wantedness series, in the hope of improving the quality of reporting: "The next few questions are important. They are about how you felt when you became pregnant." In the NSFG pretest, similar preambles improved the quality of reporting on other topics (Research Triangle Institute, 1994). Second, two questions were added to the wantedness series itself. The goal was to make the questions clearer but to preserve the ability to measure changes in unintended pregnancy over time. The 1995 NSFG asks the standard version

OCR for page 286
--> of wantedness questions, but this is followed by a new question that confirms that respondents who report an unwanted pregnancy mean that they did not want to become pregnant then or at any time in the future: So when you became pregnant, you thought you did not want to have any children at any time in your life, is that correct? The 1995 NSFG also includes a new question to clarify the meaning of a "mistimed" pregnancy: How much sooner than you wanted did you become pregnant? (Record answer in months or years.) Measuring Ambivalence about Pregnancy NSFG and RTI staff designed a series of questions to measure ambivalence about pregnancy. They patterned questions after an instrument developed and used by Irene M. Rich. Rich's questionnaire measured ambivalent feelings during pregnancy (Rich, 1993). The NSFG and RTI staff designed similar questions to measure ambivalence about becoming pregnant, that is, to measure ambivalent feelings at the time of conception. The questions, which follow, were tested in the NSFG pretest in 1993 and will be asked in the 1995 NSFG of women under 25 years of age. Question E-9. Please look at the scale on Card E-3 and tell me which number on the card best describes how you felt when you found out you were pregnant. On this scale, a one means that you were very unhappy to be pregnant and a ten means that you were very happy to be pregnant. Next, I am going to read a list of feelings and concerns women sometimes have about becoming pregnant. Please look at the scale on Card E-4.

OCR for page 286
--> Question E-10. For each statement I read, please tell me which number on the card best describes your opinion about becoming pregnant. On this scale, a one means that you strongly disagree with the statement and a ten means you strongly agree with the statement. You were worried that you did not know enough about how to take care of a baby. You thought that a new baby would keep you from doing the things that you were used to doing like working, going to school, going out and so on. You looked forward to teaching and caring for a new baby. You looked forward to the new experiences that having a baby would bring. You looked forward to experiencing the changes in your body that come with carrying a baby. You looked forward to telling your friends that you were pregnant. You were worried about what being pregnant would do to your body. You were worried that you did not have enough money to take care of a baby. You dreaded telling your friends that you were pregnant. You looked forward to buying things for a new baby. Improving Questions on Unplanned Pregnancies and Use of Contraception NSFG staff have added method-specific questions about how consistently women used contraception before becoming pregnant. The goal is to get a better

OCR for page 286
--> sense of how many unplanned pregnancies occurred while methods were being used consistently and correctly and how many stemmed from incorrect or irregular use of contraception. The new questions follow. For users of birth control pills: Question E-11. In the month before you became pregnant, how many pills that you were supposed to take did you miss? Would you say you … Never missed a pill, 1 Missed only one pill, or 2 Missed two or more pills? 3 For users of rhythm or natural family planning: Question E-12. In the month before you became pregnant, did you have intercourse during your "safe time only," during your "safe time" and at other times, or during other times only? Safe time only 1 Safe time and other times 2 Other times only 3 For users of other (coitus-dependent) methods: Question E-13. Although you were still using a method in the month before you became pregnant, how often did you and your partner usually use a method of birth control for any reason? Would you say you used a method … Less than half the time, 1 About half the time, 2 More than half the time, or 3 Every time you had intercourse? 4 The A-CASI section of the questionnaire may also improve data on unplanned pregnancy by giving respondents a second chance to accurately report their contraceptive use. During the in-person part of the interview, respondents who fail to report abortions may also fail to report their contraceptive use accurately. For example, a woman who used a contraceptive method inconsistently and who as a result had an unplanned pregnancy and an abortion may be reluctant to report this information to the interviewer and may instead report a period of successful contraceptive use. To address this possibility, the A-CASI section of the 1995 NSFG follows up any new reports of abortions with a set of

OCR for page 286
--> questions about the contraceptive method the woman used before she became pregnant: So that we can understand how well birth control methods work, we would like you to list the methods of birth control you were using—if you used any—during the month you became pregnant. Question J-1. In (month and year of conception), the month you became pregnant, were you using any birth control methods? Yes 1 (go to question J-2) No 2 (flow check question J-7) Question J-2. Which methods did you use in (month and year of conception), the month you became pregnant? Did you use …   Yes No Birth control pills? 1 2 Condoms? 1 2 A vasectomy? 1 2 A diaphragm? 1 2 Foam? 1 2 Jelly or cream? 1 2 A cervical cap? 1 2 A suppository or insert? 1 2 The Today sponge? 1 2 A female condom? 1 2 An intrauterine device? 1 2 Norplant? 1 2 Depo-provera injectables? 1 2 Rhythm or safe period by calendar? 1 2 Safe period by temperature or cervical mucus test or natural family planning? 1 2 Withdrawal? 1 2 Some other method? 1 2 Flow check question J-6: If more than one method reported in question J-2, ask question J-3. Else, go to question J-4. Question J-3. Did you use those methods together, that is, at the same time, or did you use them at different times during the month? Same time 1 (go to question J-4) Different times 2 (go to question J-4)

OCR for page 286
--> Question J-4. How many months in a row had you been using that method when you became pregnant? __________ (Number of months, ranging from 0 to 360) Finally, the 1995 NSFG uses a memory aid that may, among other benefits, improve data on contraception. NSFG staff have designed a calendar for respondents to refer to throughout the interview to help them remember the dates of the events that they report. A respondent writes important events on the calendar as she proceeds through the interview, such as her date of marriage, the dates of birth of her children, and dates when she was not having sexual intercourse for an extended time. The hope is that giving the woman a context in which to remember her contraceptive use will produce more accurate data. The trends in unintended pregnancy seem clear and their measurement fairly straightforward. The NSFG is striving to improve the measurement of the more elusive concepts related to unintended pregnancy. It is hoped that the NSFG will continue to take the lead in producing the data needed to understand the causes of unintended pregnancy. References Baldwin AK, Jobe JB, London KA, Rasinski KA, Pratt WF, Tourangeau R. Answering sensitive questions in a health survey. Forthcoming. Jones E, Forrest J. Underreporting of abortion in surveys of U.S. women: 1976–1988. Demography. 1992;29:113–126. Piccinino, LJ. Unintended pregnancy and childbearing. In From Data to Action. Wilcox L. Marks J, eds. Washington, DC: U.S. Department of Health and Human Services and Centers for Disease Control and Prevention; Forthcoming. Pratt WF, Peterson LS, Piccinino LJ. Trends in Contraceptive Practice and Contraceptive Choice, United States: 1965–1990. Paper presented at the NIH Conference on Opportunities in Contraception: Research and Development. Bethesda, MD: National Institutes of Health; 1992. Research Triangle Institute. National Survey of Family Growth, Cycle V, Pretest Report. Research Triangle Park: Research Triangle Institute; 1994. Rich IM. General Pregnancy Attitudes, Ambivalence, and Psychological Symptom Distress During Pregnancy. Ph.D.dissertation. Catholic University of America; 1993. Williams LB, London KA. The planning status of births to ever-married women in the United States: 1982-1988. Fam Plann Perspect. 1992;26:121–124.