A retrospective study using birth registry data containing information on cannabis use during pregnancy, found an association between prenatal cannabis use and the incidence of autism spectrum disorder (ASD) in the offspring, according to a research letter published in Nature Medicine.
The analysis appraised the association between cannabis exposure in pregnancy and neurodevelopmental outcomes in childhood.
The primary analysis (n=503,065) assessed prenatal cannabis use and incidence of ASD diagnosis (median length of follow-up, 7.4 years), while the secondary analysis (n=497,821) assessed the association between prenatal cannabis use and incidence of neurodevelopmental disorders.
The incidence of ASD was 4.00 per 1,000 person-years among children with exposure compared to 2.42 among unexposed children. This association was robust after controlling for confounding.
Children with prenatal cannabis exposure appeared to have some increased risk for developing intellectual disabilities, learning disorders and attention deficit, hyperactivity and conduct disorders (ADHD) compared to unexposed children, but these associations were less statistically robust.
The researchers conclude that children with mothers who reported cannabis use in pregnancy were at higher risk for ASD diagnosis and suggest that further study is needed on the amount and timing of cannabis use in pregnancy and childhood health outcomes.