Pre-pregnancy sleep duration and postpartum depression: a multicenter study in Japan.

Postpartum depression (PPD) is as a major public health issue and clinical priority worldwide. This study aimed to investigate the association between pre-pregnancy sleep duration and PPD. A multicenter retrospective study was conducted using clinical data of women who delivered at term between 2014 and 2018 at 12 maternity care hospitals in Japan. A total of 15,314 women were stratified into five groups according to their pre-pregnancy sleep duration: < 6, 6-7, 7-8, 8-9, and ≥ 9 h. Univariate and multivariate regression analyses were conducted to determine whether pre-pregnancy sleep duration affects the Edinburgh Postnatal Depression Scale (EPDS) scores at 1 month postpartum. We also evaluated whether the risk for PPD differs between primipara and multipara women classified according to pre-pregnancy sleep duration. The adjusted odds ratio for high EPDS scores (≥ 9) among women who slept for < 6 h and 6-7 h was 2.08 (95% confidence interval [CI]: 1.60-2.70) and 1.41 (95% CI: 1.18-1.68), respectively, relative to that in women with 7-8 h of sleep as the reference group. A 1-h increase in sleep duration was associated with an approximately 14% reduction in the risk for high EPDS scores. The association between short sleep duration and high EPDS scores was more remarkable in multipara women than in primipara women. Short pre-pregnancy sleep duration is associated with high EPDS scores, and this association is more significant in multipara women than in primipara women. Our findings emphasize the importance of collecting information on pre-pregnancy sleep duration to identify women at a high risk for PPD.