Omega-3 Fatty Acid Deficiency in Infants before Birth Identified Using a Randomized Trial of Maternal DHA Supplementation in Pregnancy

Randomized placebo-controlled trial in healthy pregnant women in Vancouver, Canada with uncomplicated pregnancies, enrolled around 16 weeks gestation and followed through delivery. In the DHA arm, 132 women were randomized; infant outcomes were assessed after birth through 18 months of age.

Maternal DHA supplementation was given as 400 mg/day DHA in algal oil triglycerides, taken orally in capsules from enrolment until delivery. The comparator was placebo capsules containing corn and soybean oil.

Maternal DHA supplementation reduced the risk of lower early language performance, but it did not clearly improve cognitive or motor outcomes at 18 months. Compared with placebo, the DHA group had lower odds of failure to achieve high language measures, including words understood at 14 months (OR 3.22, 95% CI 1.49-6.94, P = 0.002), words produced at 14 months (OR 2.61, 1.22-5.58, P = 0.009), words understood at 18 months (OR 2.77, 1.23-6.28, P = 0.01), and BSID-III receptive language at 18 months (OR 2.23, 1.08-4.60, P = 0.03). High visual acuity failure was also less common at 2 months (OR 2.50, 1.02-6.14, P = 0.03), but the 12-month visual acuity result was not significant (OR 1.23, 0.61-2.49, P = 0.35). BSID-III cognitive and motor outcomes were null, and the authors interpreted the findings as evidence that fetal DHA insufficiency can constrain language development in early life.

Follow-up was limited to 18 months, so longer-term developmental effects are unknown. Several outcomes were tested, increasing the chance of chance findings, and some analyses used smaller numbers than the randomized active-arm sample. Generalizability is limited to healthy term pregnancies in one Canadian setting.