Low paternal postpartum depression buffers the association between maternal prenatal depression and preschoolers' internalizing and externalizing symptoms.

Examining the impact and interplay of maternal and paternal perinatal mental health problems enhances understanding of the etiology of mental health problems in early childhood. This study investigated associations between maternal and paternal prenatal (first trimester) and postnatal (3 and 30 months) anxiety and depression symptoms and preschoolers' internalizing and externalizing symptoms. The sample included 115 preschoolers and their parents (N = 230) recruited during the first trimester of pregnancy at a Portuguese health facility. Mothers and fathers completed anxiety and depression measures during the first trimester, at 3 and 30 months postpartum, and the Child Behavior Checklist 1.5-5 (CBCL) at 30 months. Multilevel linear models and moderation models were tested. Maternal depression symptoms in the first trimester, paternal depression symptoms at 3 months postpartum, and their interplay were prospectively associated with higher preschoolers' internalizing and externalizing scores at 30 months. When fathers reported low depression symptoms 3 months postpartum, mothers' depression symptoms during the first trimester were not associated with preschoolers' internalizing and externalizing scores at 30 months. This suggests that low paternal postnatal depression symptoms can buffer the adverse effect of maternal prenatal depression symptoms. Addressing maternal and paternal perinatal mental health could contribute to preventing preschoolers' internalizing and externalizing problems.