Effect of prenatal supplementation with docosahexanoic acid on infant development: a randomized placebo‐controlled trial in Mexico.

The omega‐3 fatty acid docosahexanoic acid (DHA) is deposited in the brain early in life and plays an important role in neural and visual function. Little is known however about the benefits of ingesting DHA supplements during pregnancy for infant development. We conducted a randomized double‐blind placebo‐controlled trial of 400 mg/day algal DHA (Martek) from week 20 of gestation through delivery (n=1094 pregnant women) and followed the offspring (n=973 live births). Child development was measured in 730 children (75% of birth cohort) using the Spanish version of the Bayley Scales of Infant Development (BSID)‐II at 18 mo of age; we calculated standardized psychomotor development (PDI) and mental development indices (MDI). PDI and MDI scores (mean ± S.D.) were 94.3 ± 10.7 and 93.0 ± 8.9 in the DHA group (n=365) and 95.2 ± 9.3 and 93.3 ± 9.8 in the placebo group (n=365), respectively. Intent to treat differences in PDI and MDI scores at 18 mo were 0.90 (95% CI.: −0.55, 2.35; p=0.23) and 0.26 (95% CI.: −1.10, 1.63; p=0.70), respectively. Prenatal supplementation with 400 mg algal DHA did not result in improved global development scores at 18 mo of age in a study population (Mexico) with low intakes of DHA. Follow‐up of the cohort is ongoing. Funding: NIH (HD043099) and March of Dimes Foundation.