Background: Fetal sex is known to modify the course and complications of pregnancy, with recent evidence of sex-differential fetal influences on the maternal immune and endocrine systems. In turn, heightened inflammation and surges in reproductive hormone levels associated with pregnancy and parturition have been linked with the development of perinatal depression. Here, we examined whether there is an association between fetal sex and maternal depression assessed during the prenatal and

more »

... al periods. Methods: The study included two multi-ethnic, prospective pregnancy cohorts that enrolled women from prenatal clinics in the Northeastern United States between 2001 and 2018. Maternal depressive symptoms were measured during the prenatal and postnatal periods using the Edinburgh Postpartum Depression Scale (EPDS) and newborn sex was reported by the mother following delivery. We used logistic regression to examine associations between fetal sex and maternal depressive symptoms (EPDS>10) during the prenatal period only, postnatal period only, or both periods versus no depressive symptoms during either period. We considered both unadjusted models and models adjusted for a core set of sociodemographic and lifestyle variables. Results: In adjusted models using PRISM data (N=528), women pregnant with a male versus female fetus had significantly greater odds of depressive symptoms during the postnatal period compared to women without depressive symptoms during either period (odds ratio [OR] = 5.24, 95% confidence interval [CI] = 1.93, 14.21). The direction of results was consistent in the ACCESS cohort, although the findings did not reach statistical significance (OR = 2.05, 95% CI = 0.86, 4.93). Significant associations were not observed in either cohort among women with prenatal symptoms only or women with prenatal and postnatal symptoms. Conclusions: Male fetal sex was associated with the onset of depressive symptoms during the postnatal period.