Association of income and education with fecundability in a North American preconception cohort

Purpose: The purpose of this study is to evaluate socioeconomic determinants of fecundability.

Methods: Among 8654 female pregnancy planners from Pregnancy Study Online, a North American prospective cohort study (2013-2019), we examined associations between socioeconomic status and fecundability (the per-cycle probability of conception). Information on income and education was collected via baseline questionnaires. Bimonthly follow-up questionnaires were used to ascertain pregnancy status. We estimated fecundability ratios (FRs) and 95% confidence intervals (CIs) using proportional probabilities regression, controlling for potential confounders.

Results: Relative to an annual household income of greater than or equal to $150,000, adjusted FRs were 0.91 (95% CI: 0.83-1.01) for less than $50,000, 0.99 (95% CI: 0.92-1.07) for $50,000-$99,000, and 1.09 (95% CI: 1.01-1.18) for $100,000-$149,000. FRs for less than 12, 13-15, and 16 years of education, relative to greater than or equal to 17 years, were 0.90 (95% CI: 0.76-1.08), 0.84 (95% CI: 0.78-0.91), and 0.89 (95% CI: 0.84-0.95), respectively. Slightly stronger associations for income and education were seen among older women.

Conclusions: Lower levels of education and income were associated with modestly reduced fecundability. These results demonstrate the presence of socioeconomic disparities in fecundability.