Maternal polyunsaturated fatty acids and risk for autism spectrum disorder in the MARBLES high-risk study

Prior studies suggest that maternal polyunsaturated fatty acids intake during pregnancy may have protective effects on autism spectrum disorder in their children. However, they did not examine detailed timing of maternal polyunsaturated fatty acid intake during pregnancy, nor did they evaluate plasma concentrations. This study investigates whether maternal polyunsaturated fatty acids in defined time windows of pregnancy, assessed by both questionnaires and biomarkers, are associated with risk of autism spectrum disorder and other non-typical development in the children. Food frequency questionnaires were used to estimate maternal polyunsaturated fatty acid intake during the first and second half of pregnancy. Gas chromatography measured maternal plasma polyunsaturated fatty acid concentrations in the third trimester. In all, 258 mother-child pairs from a prospective cohort were included. All mothers already had a child with autism spectrum disorder and were planning a pregnancy or pregnant with another child. Children were clinically assessed longitudinally and diagnosed at 36 months. For polyunsaturated fatty acid intake from questionnaires, we only found mothers consuming more omega-3 in the second half of pregnancy were 40% less likely to have children with autism spectrum disorder. For polyunsaturated fatty acid concentrations in the third-trimester plasma, we did not observe any statistical significance in relation to the risk of autism spectrum disorder. However, our study confirmed associations from previous studies between higher maternal docosahexaenoic acid and eicosapentaenoic acid plasma concentrations in the late pregnancy and reduced risk for non-typical development. This study markedly advanced understandings of whether and when maternal polyunsaturated fatty acid intake influences risk for autism spectrum disorder and sets the stage for prevention at the behavioral and educational level.