Schmidt RJ, et al. - In this cohort study of 241 younger siblings of children with autism, researchers investigated the influence of maternal use of prenatal vitamins on the risk for autism recurrence in siblings of children with autism spectrum disorder. Outcomes revealed, in children whose mothers took prenatal vitamins in the first month of pregnancy, an autism spectrum disorder prevalence of 14.1% vs 32.7% in children whose mothers did not take prenatal vitamins during that time. Statistically significantly lower autism symptom severity and higher cognitive scores were also seen in children whose mothers took prenatal vitamins in the first month of pregnancy. This suggests an association of maternal daily intake of prenatal vitamins during the first month of pregnancy with decreases in recurrence of autism in high-risk families.