Early maternal DHA supplementation fails to modify clinical phenotypes associated with impaired placentation: A randomized, double-blind, placebo-controlled trial (DEEPER trial).

BACKGROUND

Defective deep placentation contributes to major obstetric complications, including preterm birth, preeclampsia (PE), and severe fetal growth restriction (FGR). Docosahexaenoic acid (DHA) supplementation may improve placental function, but evidence from randomized trials remains inconsistent.

OBJECTIVE

To evaluate whether early DHA supplementation modifies clinical phenotypes associated with impaired placentation.

METHODS

In this multicenter, double-blind, placebo-controlled trial (NCT02336243), singleton pregnant women <16 weeks were randomized to receive DHA 600 mg/day (n = 404) or placebo (n = 405) until delivery. The primary outcome was a composite of preterm birth ≤34 weeks, early-onset PE, or severe FGR (<3rd percentile). Analyses were performed on an intention-to-treat basis.

RESULTS

Of 844 women screened, 809 were randomized (404 DHA, 405 placebo). The trial did not reach the planned sample size, and the observed event rate was lower than expected. The primary outcome occurred in 3.47% of the DHA group and 2.96% of the placebo group (RR = 1.17; 95% CI 0.55-2.50; p = 0.685). No significant differences were observed for severe FGR (RR = 0.79; 95% CI 0.22-2.95) or early-onset PE (RR = 0.50; 95% CI 0.09-2.73). Secondary maternal and neonatal outcomes were similar. Adherence exceeded 90%, and no serious adverse events were recorded.

CONCLUSIONS

Daily DHA supplementation (600 mg) from early pregnancy was safe and well tolerated but did not demonstrate a statistically significant effect on clinical phenotypes of impaired placentation. Given that the study was underpowered, definitive conclusions regarding efficacy cannot be drawn. Future studies should explore higher-dose or targeted supplementation strategies, particularly in women with low baseline omega-3 status.

CLINICALTRIALS: gov (NCT02336243).