Prevalence of infertility in the United States as estimated by the current duration approach and a traditional constructed approach

Abstract

Objective: To estimate the prevalence of infertility using a current duration approach for comparison with a traditional constructed measure.

Design: Cross-sectional survey.

Setting: Not applicable.

Patient(s): A nationally representative sample of females aged 15-44 years.

Intervention(s): None.

Main outcome measure(s): Infertility prevalence estimated by two approaches: [1] a constructed measure derived from questions on sexual activity, contraception, relationship status, and pregnancy, and [2] a measure based on estimated time to pregnancy derived from the respondents' current duration of pregnancy attempt (i.e., current duration approach). Associations with self-reported descriptive characteristics using weighted logistic regression or parametric survival models for each respective approach.

Result(s): Infertility prevalence was approximately twofold higher using the current duration approach (15.5%; 95% confidence interval 8.6%-27.5%) vs. the constructed measure (7.0%; 95% confidence interval 6.2%-7.8%). Both methods identified similar patterns of increasing age, lower education, nulliparity, and history of gynecologic disorders as being associated with measures of impaired fecundity, whereas opposing patterns were seen for racial/ethnic identification and poverty status.

Conclusion(s): Infertility prevalence based on a current duration approach was consistent with other US prospective cohort studies with preconception enrollment. These findings underscore the importance of definition and methodologic approach for estimating the prevalence of infertility.

Published by Elsevier Inc.

Figures

Figure 1

Flow chart of women included in the (a) traditional NSFG constructed measure classified by outcome, and (b) the current duration approach classified by eligibility for inclusion in the analysis.

Figure 2

Estimation of the proportion of women not yet pregnant as a function of the number of months trying for pregnancy among (a) all women (n = 270) and (b) nulliparous women (n = 139) who reported currently trying and their duration of pregnancy attempt. The solid curve is the survival function for the time until pregnancy or end of attempt and the dotted curves indicate 95% confidence intervals (CI). The solid vertical line at 12 months corresponds to infertility estimates of (a) 15.5% (95% CI: 8.6, 27.5) and (b) 24.3% (95% CI: 12.4, 43.5) for the current duration approach. The corresponding infertility estimates represented by black circles are (a) 7.0% (95% CI: 6.2, 7.8) and (b) 13.2% (95% CI: 11.2, 15.2) based on the constructed measure.