Reproductive
A prospective study of objective preconception sleep health and fecundability Chad M. Coleman* Chad M. Coleman Amelia K. Wesselink Traci N. Bethea Andrea S. Kuriyama Tanran R. Wang Margaret Seo Jacob Pothen Joe Kossowsky Suzanne M. Bertisch Lauren A. Wise
Introduction: Fragmented sleep may inhibit routine hormonal fluctuations, which can impact ovulation and pregnancy initiation. There is epidemiologic evidence of an association between sleep and fertility; however, most studies have relied on self-reported sleep assessments, which may introduce bias.
Methods: We estimated prospectively the association between objective sleep health and fecundability, the per-cycle probability of conception, among 432 female-identified participants at risk of pregnancy in Pregnancy Study Online, a web-based preconception cohort study (2021-2023). Participants wore a study-issued Fitbit for 24 hours/day for up to two months during preconception to measure sleep characteristics, including duration (hours/day), efficiency (total sleep time divided by total time in bed), and wake after sleep onset (WASO; minutes awake after initial sleep onset). We averaged sleep measures across the first seven days of participation. Participants reported pregnancy status on bimonthly follow-up questionnaires. We used proportional probabilities regression models to estimate fecundability ratios (FRs) and 95% CIs, adjusting for socio-demographic, behavioral, and reproductive factors.
Results: Using life-table methods, 75% of participants conceived during 12 months of follow-up. The medians (interquartile ranges) for sleep duration, efficiency, and WASO were 7.2 (6.7-7.7 hours/day), 88.4% (87.1%-89.7%), and 56 (48-66 minutes), respectively. Compared with ≥7 hours/day (clinically recommended duration), FR (95% CI) for <7 hours/day was 1.08 (0.83, 1.42). The lowest quartile of sleep efficiency (≤87.0% vs. >89.0%) and highest quartile of WASO (>66.3 vs. ≤48.8 minutes) were associated with reduced fecundability (FR for sleep efficiency 0.82, 95% CI 0.55, 1.21; FR for WASO 0.73, 95% CI 0.50, 1.07). Results were consistent when exposures were modeled as continuous.
Conclusions: Reduced sleep efficiency and increased WASO may be risk factors for delayed conception.