Background: Docosahexanoic acid (DHA) is an important constituent of the brain. Evidence from well-designed intervention trials of the long-term benefits of increasing DHA intake during pregnancy has been sparse.
Objective: We evaluated global cognition, behavior, and attention at age 5 y in the offspring of Mexican women who participated in a randomized controlled trial of prenatal DHA supplementation.
Design: A total of 1094 women were randomly assigned to receive 400 mg of either DHA or placebo/d from 18 to 22 wk of pregnancy until delivery. We assessed cognitive development and behavioral and executive functioning, including attention, in 797 offspring at age 5 y (82% of 973 live births) with the use of the McCarthy Scales of Children’s Abilities (MSCA), the parental scale of the Behavioral Assessment System for Children, Second Edition (BASC-2), and the Conners’ Kiddie Continuous Performance Test (K-CPT). We compared the groups on raw scores, T-scores, and standardized scores, as appropriate. We examined heterogeneity by the quality of the home environment, maternal intelligence, and socioeconomic status.
Results: There were no group differences for MSCA scores (P > 0.05), but the positive effect of the home environment at 12 mo on general cognitive abilities was attenuated in the DHA group compared with in the placebo group (P-interaction < 0.05). There were no differences between groups on the BASC-2. On the K-CPT, offspring in the DHA group showed improved mean ± SD T-scores compared with those of the placebo group for omissions (DHA: 47.6 ± 10.3; placebo: 49.6 ± 11.2; P < 0.01) with no differences (P > 0.05) for the other K-CPT scores or of the proportion who were clinically at risk of attention deficit hyperactivity disorders after Bonferroni correction for multiple comparisons.
Conclusion: Prenatal exposure to DHA may contribute to improved sustained attention in preschool children. This trial was registered at clinicaltrials.gov as NCT00646360.