120: Prenatal, peri-natal, and neonatal risk factors for autism in California, 1991-2001


      Examine prenatal, peri-natal, and neonatal risk factors on the incidence of autism.

      Study Design

      Retrospective cohort population based study. Records of children with autism spectrum disorders (ASD) from the California Department of Developmental Services were linked with their hospital birth records from 1991-2001 and were examined for demographics, obstetric and neonatal outcomes and compared to all children without ASD born during the same period.


      20,206 children with ASD were identified and their records examined and compared to those children without ASD. Demographic factors including advancing maternal age OR 2.0 (95% CI 1.9, 2.1) 35-40 years as compared to 21-25 years, advanced level of education OR 1.9 (1.8, 2.0) college vs < high school, nulliparity OR 2.0 (1.9, 2.2) compared to para 3 or more, and race other than white OR 1.3 (1.22, 1.37) for African American vs. White, were all associated with increased risk of ASD. Maternal diabetes had a slight increase risk OR 1.13 (1.05-1.21) for gestational diabetes, and OR 1.30 (1.10-1.53) with pre-existing diabetes. Birth weight (besides infants >4000gm OR 1.25 (1.20, 1.30)) did not impact incidence of ASD, but being male did with OR 4.62 (4.45-4.80). Adverse obstetric events (birth asphyxia, fetal distress, birth trauma, prematurity, mode of delivery) did not increase the risk of developing ASD. With the exception of IVH OR 1.46 (1.12, 1.9), complications in the newborn period (RDS, necrotizing enterocolitis, IUGR) were likewise not associated with an increased risk of ASD.


      Clearly, the vast majority of adverse obstetrical and neonatal outcomes were not associated with an increased risk of having a child who subsequently develops ASD. Certain demographic factors, on the other hand, were highly associated with ASD and areas of research should focus in these areas.