Supplementation in pregnant women with docosahexaenoic acid and its effect on children's cognitive processes: Systematic review

Abstract

Introduction: Docosahexaenoic acid (DHA) is deposited in brain regions involved in neuronal and functionality. Due to this important participation, it is considered to be a key factor in the development of the central nervous system. The objective was to analyze the results of studies on the influence of docosahexaenoic acid (DHA) supplementation in pregnant women on the cognitive processes of their children. Material and Methods: Systematic review of randomized controlled trials with DHA supplementation in pregnant women considering the guidelines of the Cochrane group. From January 2003 to May 2018 a search for scientific articles in MEDLINE, EMBASE, Scopus and the Cochrane Library was made. Studies were selected that compared the effects of supplementation in pregnant women with those of placebo with respect to evaluations of cognitive processes. The risk of bias was evaluated with the Cochrane collaboration tool. Results: 147 scientific articles were found, choosing 10 that had as their methodological characteristics the double-blind randomized. The studies involved 4506 pregnant women between 15 and 21 weeks and 2045 children. Supplementation was given between week fifteen and three months after delivery. The age of the first evaluation varied between one and a half and four years. Six instruments and two execution batteries were used to measure 19 cognitive processes. Only two of the studies reported significant differences between the subjects of control and experimental group. Due to the heterogeneity between the studies in relation to the sample sizes, the doses and the way of measuring the variable of interest, it was not possible to perform a meta-analysis. Conclusions: Scientific evidence is insufficient to affirm or deny a positive effect of early supplementation with DHA in children's cognitive processes. The recommendation of the use of supplements with DHA during the gestational period to favor them is not justified.