Female sleep patterns, shift work, and fecundability in a North American preconception cohort study.

Abstract

OBJECTIVE\nTo prospectively evaluate the association between female sleep patterns, shift work, and fecundability.\n\n\nDESIGN\nWeb-based preconception cohort study, Pregnancy Study Online (PRESTO).\n\n\nSETTING\nNot applicable.\n\n\nPATIENT(S)\nNorth American Women aged 21-45\xa0years attempting pregnancy.\n\n\nINTERVENTION(S)\nNot applicable.\n\n\nMAIN OUTCOME MEASURE(S)\nAt baseline, self-reported average sleep duration per 24-hour period in the previous month, the frequency of trouble sleeping within the last 2\xa0weeks (as measured by the Major Depression Inventory), and shift work patterns. Pregnancy status determined by follow-up questionnaires completed every 8\xa0weeks for up to 12\xa0months or until conception.\n\n\nRESULT(S)\nThe analyses were restricted to 6,873 women attempting pregnancy for ≤6\xa0months at enrollment from June 2013 through September 2018. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), adjusting for potential confounders. Relative to 8\xa0hours of sleep per day, FRs for <6, 6, 7, and ≥9\xa0hours of sleep/day were 0.89 (95% CI, 0.75-1.06), 0.95 (95% CI, 0.86-1.04), 0.99 (95% CI, 0.92-1.06), and 0.96 (95% CI, 0.84-1.10), respectively. Compared with no trouble sleeping, FRs for trouble sleeping <50% of the time or trouble sleeping >50% of the time were 0.93 (95% CI, 0.88-1.00) and 0.87 (95% CI, 0.79-0.95), respectively. The results were slightly stronger among women with higher depressive symptoms and perceived stress levels. There was no association between shift work and fecundability.\n\n\nCONCLUSION(S)\nTrouble sleeping at night was associated with modestly reduced fecundability. A weaker inverse association was observed between shorter sleep duration and fecundability.