A western dietary pattern during pregnancy is associated with neurodevelopmental disorders in childhood and adolescence.

Despite the high prevalence of neurodevelopmental disorders, the influence of maternal diet during pregnancy on child neurodevelopment remains understudied. Here we show that a western dietary pattern during pregnancy is associated with child neurodevelopmental disorders. We analyse self-reported maternal dietary patterns at 24 weeks of pregnancy and clinically evaluated neurodevelopmental disorders at 10 years of age in the COPSAC2010 cohort (n = 508). We find significant associations with attention-deficit hyperactivity disorder (ADHD) and autism diagnoses. We validate the ADHD findings in three large, independent mother-child cohorts (n = 59,725, n = 656 and n = 348) through self-reported dietary modelling, maternal blood metabolomics and foetal blood metabolomics. Metabolome analyses identify 15 mediating metabolites in pregnancy that improve ADHD prediction. Longitudinal blood metabolome analyses, incorporating five time points per cohort in two independent cohorts, reveal that associations between western dietary pattern metabolite scores and neurodevelopmental outcomes are consistently significant in early-mid-pregnancy. These findings highlight the potential for targeted prenatal dietary interventions to prevent neurodevelopmental disorders and emphasise the importance of early intervention.