Gestational weight gain and risk factors for postpartum depression symptoms from the Japan Environment and Children's Study: a prospective cohort study

Background: : The relationship between postpartum depression symptoms (PPDS) and gestational weight gain is controversial. We aimed to examine the risk of gestational weight gain for PPDS at 1 month postpartum based on the pre-pregnancy body mass index (BMI). Methods:: A prospective cohort study recruited 80 927 Japanese women 2011-2014. They categorized according to their pre-pregnancy BMI into group 1 (<18.5 kg/m(2)), group 2 (18.5 to <20.0 kg/m(2)), group 3 (20.0 to <23.0 kg/m(2)), group 4 (23.0 to <25.0 kg/m(2)), and group 5 (<25.0 kg/m(2)). Multiple logistic regression analysis was performed for each BMI category to identify potential risk factors of insufficient or excessive gestational weight gain associated with PPDS, following adjustments for maternal age, education, annual household income, smoking, parity, mode of delivery, cessation of breast feeding, psychological stress, and daily energy intakes during pregnancy. Results: : Among participants in group 3, insufficient gestational weight gain was a risk factor for PPDS (adjusted odds ratio: 1.24, 95% confidence interval: 1.14-1.36). This result was not modified by intermediate factors. Limitations:: The criteria of appropriate gestational weight gain were determined from the adverse pregnancy outcomes not validated for PPDS. Other confounding factors for PPDS like psychotic disorders were not examined. Conclusions: : For women with a pre-pregnancy BMI between 20.0 and <23.0 kg/m(2), insufficient gestational weight gain is a risk factor for PPDS. Therefore, monitoring gestational weight gain is recommended for the early detection of PPDS in these women.