Gestational Age, Perinatal Characteristics, and Autism Spectrum Disorder: A Birth Cohort Study.

Objective To determine how gestational age relates to research-identified autism spectrum disorder (ASD-R) in the context of perinatal risk factors. Study design This is a population-based cohort study using the 1994-2000 Olmsted County Birth Cohort. Children included were born and remained in Olmsted County after age 3 years. ASD-R status was determined from signs and symptoms abstracted from medical and educational records. Cox proportional hazards models were fit to identify associations between perinatal characteristics and ASD-R. Results The incidence of preterm birth ( Conclusions The increased risk of ASD-R among children born preterm relative to children born full term was attenuated by infant and maternal characteristics.