Randomized controlled trial of maternal omega-3 long-chain PUFA supplementation during pregnancy and early childhood development of attention, working memory, and inhibitory control.

Randomized, placebo-controlled follow-up of the DOMInO trial in pregnant women with singleton pregnancies enrolled at 18 to 21 weeks' gestation in Adelaide, Australia. Overall, 185 term-born children were randomized, with 81 assessed in the DHA arm and 77 in the placebo arm at about 27 months of age.

Maternal oral DHA-rich capsules were given as three 0.5-g capsules per day, providing 800 mg DHA/day and 100 mg EPA/day, from about 20 weeks' gestation until delivery. The active regimen was compared with identical placebo capsules.

Prenatal DHA supplementation did not improve attention or working memory/inhibitory control in term-born preschoolers, and there were no consistent benefits across outcomes. Primary outcomes were null: distractibility mean difference -0.2 s (95% CI -0.7, 0.4 s) and WMIC mean difference 8.9 mm (95% CI -0.6, 28.3 mm). A secondary attention outcome also showed no clear advantage, with an adjusted mean difference of 22.0 looks; 95% CI: 23.9 to 20.2 looks. Overall, any observed differences were considered likely to be due to chance.

Only 81 DHA-arm and 77 placebo-arm children were assessed at follow-up, so power was limited. Outcomes were measured at a single time point in preschool age, and one baseline characteristic differed between groups, with more fathers in the DHA arm having completed secondary education. Adverse events were not reported in the text, and the cord plasma DHA subgroup analyses were smaller still.