Prepregnancy BMI, gestational weight gain, and susceptibility to autism‐related traits: the EARLI and HOME studies

Abstract Objective Excessive gestational weight gain (GWG) has been associated with autism spectrum disorder (ASD). This study sought to examine whether familial susceptibility for autism, intensity of ASD‐related behaviors, or prepregnancy BMI influences the association of GWG with ASD‐related behaviors. Methods Using data from the Early Autism Risk Longitudinal Investigation (EARLI) study ( n = 136), a familial enriched cohort of mothers who had a previous child with ASD, and the Health Outcomes and Measures of the Environment (HOME) study ( n = 253), a general population cohort, gestational age and prepregnancy BMI category‐specific GWG z scores were calculated. Caregivers completed the Social Responsiveness Scale (SRS) to assess the presence and severity of ASD‐related traits in children aged 3 to 8 years. Using quantile regression, the association between GWG z scores and ASD‐related behaviors in children was estimated. Results In HOME, among mothers who had overweight or obesity prepregnancy BMI values, GWG z scores and SRS scores were positively associated in children with more ASD‐related traits (higher SRS scores), but not in children with fewer ASD‐related traits. Similar patterns were observed in EARLI among mothers with prepregnancy obesity. Conclusions GWG may be associated with autism‐related behaviors among children who have a greater predisposition to these behaviors and who have mothers with prepregnancy overweight or obesity.