Maternal Pre-Pregnancy BMI and Gestational Weight Gain Modified the Association between Prenatal Depressive Symptoms and Toddler’s Emotional and Behavioral Problems: A Prospective Cohort Study

Background: Maternal prenatal depressive symptoms and abnormal pre-pregnancy BMI have been scarcely reported to play interactive effects on child health. In this prospective cohort, we aimed to examine the interactive effects of maternal prenatal depressive symptoms and pre-pregnancy BMI as well as gestational weight gain (GWG) on offspring emotional and behavioral problems (EPBs). Methods: The study samples comprised 1216 mother–child pairs from Shanghai Maternal–Child Pairs Cohort recruited from 2016 to 2018. Maternal pre-pregnancy BMI and GWG were obtained from medical records, and maternal depressive symptoms were assessed via the Center for Epidemiological Studies Depression Scale (CES-D) at 32–36 gestational weeks. The child completed the behavioral measurement via the Strengths and Difficulties Questionnaire (SDQ) at 24 months postpartum. Results: There were 12.01% and 38.65% women with prenatal depressive symptoms and sub-threshold depressive symptoms during late pregnancy. Both maternal depressive symptoms and prenatal sub-threshold depressive symptoms were associated with higher internalizing (OR = 1.69, 95% CI, 1.05–2.72; OR = 1.48, 95% CI, 1.06–2.07) and externalizing (OR = 2.06, 95% CI, 1.30–3.25; OR = 1.42, 95% CI, 1.02–1.99) problems in children. Maternal pre-pregnancy BMI and GWG modified the association between prenatal depressive symptoms and child externalizing or total difficulties problems (p < 0.10 for interaction). Among the overweight/obese pregnant women, maternal prenatal depressive symptoms were associated with a higher risk of externalizing problems (OR = 2.75, 95% CI, 1.06–7.11) in children. Among the women who gained inadequate GWG, maternal prenatal sub-threshold depressive symptoms were associated with 2.85-fold (95% CI 1.48–5.48) risks for child externalizing problems, and maternal depressive symptoms were associated with higher externalizing and total difficulties problems (OR = 4.87, 95% CI, 2.03–11.70 and OR = 2.94, 95% CI, 1.28–6.74, respectively), but these associations were not significant in the appropriate or excessive GWG group. Conclusions: Both maternal prenatal sub-threshold depressive symptoms and depressive symptoms increased the risks of child internalizing and externalizing problems at 24 months of age, while the effects on child externalizing problems were stronger among overweight/obese or inadequate GWG pregnant women. Our study highlights the importance of simultaneously controlling the weight of pregnant women before and throughout pregnancy and prompting mental health in pregnant women, which might benefit their offspring’s EBPs.