Studies in the general population have proposed links between nutrition and depression, but less is
known about the perinatal period. Depletion of nutrient reserves throughout pregnancy and delayed
postpartum repletion could increase the risk of perinatal depression. We examined the relationships of
plasma folate and vitamin B12 concentrations during pregnancy with perinatal depression. At 26the28th
weeks of gestation, plasma folate and vitamin B12 were measured in women from the GUSTO motheroffspring
cohort study in Singapore. Depressive symptoms were measured with the Edinburgh Postnatal
Depression Scale (EPDS) during the same period and at 3-month postpartum. EPDS scores of 15 during
pregnancy or 13 at postpartum were indicative of probable depression. Of 709 women, 7.2% (n ¼ 51)
were identified with probable antenatal depression and 10.4% (n ¼ 74) with probable postnatal
depression. Plasma folate concentrations were significantly lower in those with probable antenatal
depression than those without (mean SD; 27.3 13.8 vs 40.4 36.5 nmol/L; p ¼ 0.011). No difference
in folate concentrations was observed in those with and without probable postnatal depression. In
adjusted regression models, the likelihood of probable antenatal depression decreases by 0.69 for every
unit variation (increase) in folate (OR ¼ 0.69 per SD increase in folate; 95% CI: 0.52, 0.94). Plasma vitamin
B12 concentrations were not associated with perinatal depression. Lower plasma folate status during
pregnancy was associated with antenatal depression, but not with postnatal depression. Replication in
other studies is needed to determine the direction of causality between low folate and antenatal
depression.
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