Prenatal Environment and Perinatal Factors Associated with Autism Spectrum Disorder

Background: Both genetic and epidemiological studies have indicated that environmental factors play an essential role in the development of autism spectrum disorder (ASD). We conducted this study to identify maternal exposure to environmental factors, in particular during the fetal development or perinatal period, associated with ASD. Methods: Two independent samples of children with ASD and typical developed (TD) were from distinct regions in China. Multiple logistic regression analysis was performed to identify factors associated with ASD in each sample and then in the combined sample. Results: Five factors were consistently associated with ASD in both samples. In the combined sample, maternal chemical exposure (odds ratio [OR] =4.50; 95% CI: 2.38-8.52), use of medication (OR = 3.19; 95% CI: 2.19-4.65), maternal infection (OR = 2.68; 95% CI: 1.99-3.61), threatened abortion (OR = 2.37; 95% CI: 1.61-3.50), and induced abortion before having the child (OR = 2.07; 95% CI: 1.65-2.60) showed strong associations with ASD; moreover, five factors explained 10-15% of the variation in the risk of ASD. A significant interaction between maternal infection and the use of medication during pregnancy was consistently detected in both independent and combined samples together. Conclusion: Two novel risk factors of maternal chemical exposure and induced abortion may have important implications for understanding the etiology of ASD, particularly in China. Prospective studies are needed to validate these findings, and necessary interventions are recommended to reduce the risk of ASD. KEYWORDS Autism spectrum disorder, chemical exposure, induced abortion, maternal infection