The association between time-to-pregnancy and postpartum depressive symptoms in a North American prospective cohort study.

<bold>Purpose: </bold>To prospectively examine the association between time-to-pregnancy (TTP) and postpartum depression (PPD) and determine whether perceived stress during early pregnancy mediated this association.<bold>Methods: </bold>In Pregnancy Study Online, an internet-based preconception cohort study of pregnancy planners, participants completed questionnaires every 8 weeks for up to 12 months or conception, during pregnancy, and at postpartum. A total of 2643 women provided information on sociodemographic factors, reproductive history, and stress (i.e., Perceived Stress Scale [PSS]) during preconception and early pregnancy (completed at ∼4-12 weeks' gestation) and on postpartum depressive symptoms (i.e., Edinburgh Postnatal Depression Scale [EPDS]) at ∼6 months postpartum. We used multivariable modified Poisson regression models to estimate risk ratios and 95% confidence intervals (CIs) for the association between TTP (<3, 3-5, 6-11, ≥12 menstrual cycles) and PPD (EPDS score ≥13). Causal mediation analyses assessed the mediating role of early pregnancy PSS scores.<bold>Results: </bold>10.6% of women had EPDS scores indicating possible PPD (≥13). Compared with women who took less than 3 cycles to conceive, risk ratios for those who took 3-5, 6-11, and greater than or equal to 12 were 1.06 (95% CI: 0.77, 1.45), 1.24 (95% CI: 0.90, 1.70), and 1.31 (95% CI: 0.87, 1.99), respectively. Approximately 30% of the association between infertility (TTP ≥ 12) and PPD was mediated by early pregnancy PSS.<bold>Conclusions: </bold>There was a modest positive dose-response association between delayed conception and PPD. Perceived stress in early pregnancy explained a small proportion of this association. However, given the width of the CIs, chance cannot be ruled out as an explanation for the observed association. [ABSTRACT FROM AUTHOR]