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

We evaluated prospectively the association between sleep patterns and fecundability among pregnancy planners. Trouble sleeping and short sleep duration were modestly associated with reduced fecundability.

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Volume 111, Issue 6, Pages 1201–1210.e1


Sydney Kaye Willis, M.S.P.H., Elizabeth Elliott Hatch, M.S., Ph.D., Amelia Kent Wesselink, M.P.H., Ph.D., Kenneth Jay Rothman, Dr.P.H., Ellen Margrethe Mikkelsen, R.N., M.P.H., Ph.D., Lauren Anne Wise, M.Sc., Sc.D.



To prospectively evaluate the association between female sleep patterns, shift work, and fecundability.


Web-based preconception cohort study, Pregnancy Study Online (PRESTO).


Not applicable.


North American Women aged 21–45 years attempting pregnancy.


Not applicable.

Main Outcome Measure(s)

At baseline, self-reported average sleep duration per 24-hour period in the previous month, the frequency of trouble sleeping within the last 2 weeks (as measured by the Major Depression Inventory), and shift work patterns. Pregnancy status determined by follow-up questionnaires completed every 8 weeks for up to 12 months or until conception.


The analyses were restricted to 6,873 women attempting pregnancy for ≤6 months 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 hours of sleep per day, FRs for <6, 6, 7, and ≥9 hours 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.


Trouble sleeping at night was associated with modestly reduced fecundability. A weaker inverse association was observed between shorter sleep duration and fecundability.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders.