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Unintended Childbearing: Pregnancy Risk Assessment Monitoring System -- Oklahoma, 1988-1991

Unintended pregnancies may be associated with delays in the initiation of prenatal care and behaviors during pregnancy that increase the risk for adverse birth outcomes (1,2). Based on estimates from the 1988 National Survey of Family Growth, 28% of births were mistimed during the 3-4 years before the survey, and 12% were unwanted (3). In Oklahoma, family-planning services are provided as an element of the state's maternal and child health program efforts, and the state has made a priority of identifying mothers at high risk for unintended pregnancy. This report summarizes an analysis of data from the Oklahoma Pregnancy Risk Assessment Monitoring System (PRAMS) to assess the risk for unintended childbearing in Oklahoma during 1988-1991.

PRAMS is a CDC-developed, population-based surveillance system used in 13 states * and the District of Columbia that supplements information from birth certificates with self-reported behavioral information obtained from mothers 3-6 months after delivery (4). A stratified systematic sample of 100-200 new mothers is selected in each area each month from birth certificates. Sampled mothers are mailed a 14-page questionnaire approximately 5 months after they give birth. A total of 6805 women who gave birth in Oklahoma from April 1988 through March 1991 were sampled; of these, 4837 (71%) responded. Data were weighted to account for survey design and nonresponse. Confidence intervals were calculated by using the standard errors estimated by the Software for Survey Data Analysis (SUDAAN) (5).

Respondents were asked, "Thinking back to just before you were pregnant, how did you feel about becoming pregnant?" A pregnancy was classified as intended if the woman responded "I wanted to be pregnant sooner" or "I wanted to be pregnant then"; it was considered mistimed if the woman reported "I wanted to be pregnant later." Respondents reporting "I didn't want to be pregnant then or at any time in the future" were considered to have had unwanted pregnancies. Mistimed and unwanted pregnancies were classified as unintended pregnancies. Data on maternal age, race, education, number of previous live births, and birth interval were obtained from birth certificates. The PRAMS questionnaire provided data on initiation of prenatal care, marital status at conception, method of payment for delivery, and smoking status 3 months before conception.

Overall, 44.1% (95% confidence interval {CI}=41.7%-46.5%) of respondents reported that their pregnancies were unintended; of these, 30.8% (95% CI=28.0%-33.6%) reported that their pregnancies were mistimed, and 13.3% (95% CI=11.6%-15.0%) reported that their pregnancies were unwanted.

More than two thirds (69.4%) of teenaged respondents (aged less than 20 years) reported that their pregnancies were unintended, compared with 49.2% of women aged 20-24 years and 35.5% of women aged greater than or equal to 25 years (Table 1). Because young age is also associated with other risk factors such as having less than a high school education, being unmarried, and smoking, data were stratified by age when examining the relation between other factors and pregnancy status. Among women aged greater than or equal to 25 years, pregnancy intention varied by maternal education, method of payment for delivery, smoking status, and length of gestation at entry into prenatal care; however, among mothers aged less than 20 years, the rate of unintended pregnancy was high regardless of these factors. Race and marital status at conception were associated with pregnancy intention at all ages: black women and unmarried women were more likely to report that their pregnancies were unintended.

Reported by: SR DePersio, MD, W Chen, MS, D Blose, MA, R Lorenz, MSPH, W Thomas, PN Zenker, MD, State Epidemiologist, Oklahoma State Dept of Health. Div of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, CDC.

Editorial Note

Editorial Note: The potential effects of maternal behaviors -- both at conception and during pregnancy -- on birth outcomes underscores the need to monitor and characterize those behaviors. Because birth certificates contain limited information and the 1988 National Maternal and Infant Health Survey collected behavioral information but did not provide state-specific estimates, PRAMS provides participating states with such data on an ongoing basis.

The overall prevalence of unintended pregnancies among women in Oklahoma, although similar to the national prevalence of 40% (3), may be underestimated for two reasons: first, the PRAMS sample excludes women who obtained abortions and women who are the birth mothers of adopted infants; and second, because of the interval between conception and questionnaire completion, the mother may not recall whether the pregnancy was intended, or she might be reluctant to report that it was unintended. Because the data in this analysis were controlled only for age, the magnitude, direction, and significance of associations may change after adjustments for other factors (e.g., race/ethnicity and socioeconomic status).

Of all unintended births in Oklahoma, 78% occurred among women aged greater than or equal to 20 years. The associations between reported intention of pregnancy and certain behavioral and demographic factors may help structure interventions for this population. Oklahoma has begun a public- and provider-education initiative to increase awareness that unintended pregnancy is not restricted to teenagers but occurs with greater frequency among women aged greater than or equal to 20 years.

Although women aged less than 20 years accounted for only 22% of unintended pregnancies in Oklahoma, the proportion of unintended pregnancies among young women (69%) was substantially greater than that among older women. Therefore, teenagers should be offered family-planning services that are not restricted by eligibility based on income.

Limited information is available for examining the distribution and impact of prepregnancy and prenatal behaviors. PRAMS provides a means for state program managers to investigate such associations and to monitor and assess their efforts toward achieving the year 2000 national health objective of reducing unintended pregnancies to no more than 30% of all pregnancies (objective 5.2) (6).


  1. Cartwright A. Unintended pregnancy that leads to babies. Soc Sci Med 1988;27:249-54.

  2. Pamuk ER, Mosher WD, NCHS. Health aspects of pregnancy and childbirth: United States, 1982. Hyattsville, Maryland: US Department of Health and Human Services, Public Health Service, CDC, 1988; DHHS publication no. (PHS)88-1992. (Vital and health statistics; series 23, no. 16).

  3. Forrest JD, Singh S. The sexual and reproductive behavior of American women, 1982-1988. Fam Plann Perspect 1990;22:206-14.

  4. Adams MM, Shulman HB, Bruce C, Hogue C, Brogan D. The Pregnancy Risk Assessment Monitoring System: design, questionnaire, data collection, and response rates. Pediatric Perinatal Epidemiology 1991;5:333-46.

  5. Shah BV, Barnwell BG, Hunt PN, LaVange LM. Software for Survey Data Analysis (SUDAAN) version 5.50 {Software documentation}. Research Triangle Park, North Carolina: Research Triangle Institute, 1991.

  6. Public Health Service. Healthy people 2000: national health promotion and disease prevention objectives -- full report, with commentary. Washington, DC: US Department of Health and Human Services, Public Health Service, 1991; DHHS publication no. (PHS)91-50212.

    • Alabama, Alaska, California, Florida, Georgia, Indiana, Maine, Michigan, New York, Oklahoma, South Carolina, Washington, and West Virginia.

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