Neighborhood disadvantage and fecundability in a cohort of US Black women.

Background: Neighborhood context is a root cause of health disparities, but few epidemiologic studies have measured the effect of neighborhoods on fertility, a reproductive outcome with known racial disparities. Methods: The Black Women's Health Study is a prospective cohort study of US Black women who enrolled in 1995. Participants completed questionnaires at baseline and every 2 years afterwards. We linked participant addresses to US Census block group data on six variables representing neighborhood disadvantage and used factor analysis to derive a composite neighborhood disadvantage score. In 2011, participants reported how many months it took to conceive each of their planned pregnancies and whether they had ever tried to conceive for 12 or more months without success. We included 2,085 participants who contributed 2,712 pregnancy attempts during 1995-2011. We fit proportional probabilities regression models with generalized estimating equations to estimate fecundability ratios and 95% confidence intervals (CI). We stratified models by individual-level educational attainment. Results: Relative to the lowest quintile of neighborhood disadvantage, fecundability ratios for participants in quintiles 2, 3, 4, and 5 were 0.89 (95% CI = 0.79, 1.01), 0.94 (95% CI = 0.83, 1.06), 0.84 (95% CI = 0.74, 0.96), and 0.89 (95% CI = 0.79, 1.02), respectively. The association persisted only among participants with a college degree or higher. Conclusion: Higher neighborhood disadvantage was associated with reduced fecundability in this cohort of Black women, particularly among those with high educational attainment. These results support the relevance of studying place-based risk factors for subfertility and have important implications for advancing reproductive justice.