Dietary supplements for preventing postnatal depression.

Systematic review of randomized trials in pregnant women or women within 6 weeks postpartum who were not depressed at trial entry. Two studies contributed active-intervention data: Iranian primigravid women and women at elevated risk for postpartum depression in the United States.

Selenium yeast tablets 100 µg orally once daily from the first trimester of pregnancy until delivery. In the omega-3 trial, participants received either EPA-rich fish oil (1060 mg EPA + 274 mg DHA daily) or DHA-rich fish oil (900 mg DHA + 180 mg EPA daily) orally from 12 to 20 weeks' gestation until 6 to 8 weeks postpartum; placebo capsules were matched in appearance.

Overall, there is insufficient evidence that selenium, DHA, or EPA prevent postnatal depression, and no other dietary supplement can currently be recommended for prevention. In the selenium trial, postpartum EPDS scores were lower with selenium than placebo but did not reach statistical significance (MD −1.90, 95% CI −3.92 to 0.12; P = 0.07; 8.8 ± 5.1 vs 10.7 ± 4.4). In the omega-3 trial, neither EPA nor DHA improved postpartum BDI scores versus placebo (EPA MD 0.70, 95% CI −1.78 to 3.18; DHA MD −0.20, 95% CI −2.61 to 2.21), and EPA was not superior to DHA (MD 0.90, 95% CI −1.33 to 3.13).

Evidence came from only 2 randomized trials with 167 active-arm participants total, limiting precision and generalizability. Interventions, populations, and outcome measures differed across studies, and follow-up was short to early postpartum. Adverse events were not reported, and the review authors noted that more high-quality trials are needed, including trials that exclude depressed women at entry.