Maternal early life factors associated with hormone levels and the risk of having a child with an autism spectrum disorder in the nurses health study II.

It is not known whether reproductive factors early in the mother's life influence risk of autism spectrum disorders (ASD). We assessed maternal age at menarche, menstrual cycle characteristics during adolescence, oral contraceptive use prior to first birth, body shape, and body mass index (BMI) in association with ASD using binomial regression in a cohort study of 61,596 women, including 743 cases. Overall, early life factors were not associated with ASD, though early age at menarche (RR for age 10 or less = 1.54, 95% CI 1.18, 2.02, p = 0.0002) and BMI at age 18 of ≥30 (RR 2.03, 95% CI 1.34, 3.08, p = 0.0008) were significantly associated with increased risk of ASD. Further work should investigate the potential influence of these factors.