Vitamin D levels and perinatal depressive symptoms in women at risk: a secondary analysis of the mothers, omega-3, and mental health study

Pregnant women from Michigan, aged 18+, at risk for depression (EPDS 9-19 or history of depression), singleton gestation; enrolled 12-20 weeks; randomized, double-blind, placebo-controlled trial; depressive symptoms assessed with Beck Depression Inventory (BDI) at 12-20, 26-28, 34-36 weeks and 6-8 weeks postpartum; MINI used to diagnose MDD and GAD.

Omega-3 fatty acid supplementation during pregnancy: EPA-rich fish oil (1060 mg EPA + 274 mg DHA) and DHA-rich fish oil (900 mg DHA + 180 mg EPA); duration: during pregnancy.

Lower early-pregnancy 25-OH vitamin D was inversely related to BDI scores at 12-20 and 34-36 weeks (P<0.05); each 1 ng/mL increase in vitamin D at 12-20 weeks predicted about a 0.14-point lower BDI. Vitamin D was not linked to MDD or GAD diagnoses. Low vitamin D at enrollment predicted higher BDI at 34-36 weeks (P=0.05); in adjusted analyses, low vitamin D at visit 1 remained associated with higher BDI at 34-36 weeks (P=0.01); about 12% of the variance in BDI at 34-36 weeks was explained by low vitamin D plus low EPA and DHA. Vitamin D was not associated with postpartum BDI. Conclusion: adequate vitamin D in early pregnancy may help reduce depressive symptoms during pregnancy in women at risk; randomized trials are needed to test whether vitamin D supplementation in early pregnancy can prevent perinatal depressive symptoms.

Secondary analysis of a trial designed for omega-3 outcomes; not powered to detect vitamin D associations; potential confounding by omega-3 intervention; use of BDI rather than EPDS; no data on inflammatory cytokines; postpartum analyses less definitive.