Autism Spectrum Disorders (ASDs) are highly heritable, however few genetic causes have been identified and the prevalence has increased recently, suggesting that alternative genetic mechanisms may contribute, including maternal genetic effects or environmental factors that intersect with genetics to cause ASDs. We are currently working with collaborators to investigate a large pregnancy cohort with a nested case-control study and health as well as immune biomarker data. We hope to identify novel genetic maternal factors that affect risk of autism, potentially by influencing the in utero environment early in neurodevelopment. Identification of novel maternal genetic factors or genes mediating environmental exposures will provide insight into biological mechanisms, markers for prediction of ASD risk, and potential ways to reduce the risk of autism in some families.