Cannabis Use During Pregnancy Linked to Increased Autism Risk in Children

American Psychiatric Association

Mon, Aug 10, 2020

Women who use cannabis while pregnant have an elevated risk of having children with autism spectrum disorder (ASD), according to a study published today in Nature Medicine.

“Children with prenatal cannabis exposure had an increase of 50% in the risk of an autism diagnosis over the study period, and these associations were robust after controlling for confounding,” wrote Daniel Corsi, Ph.D., of the University of Ottawa and colleagues.

Corsi and colleagues analyzed the health outcomes of over 500,000 children born in Ontario between April 1, 2007, and March 31, 2012, by linking pregnancy data from Ontario’s birth registry to health administrative databases in Canada’s various provinces. Among the mothers, 0.6% reported using cannabis while pregnant.

The investigators monitored health outcomes in the children for an average of 7.4 years. During the study period, 2.2% of children with prenatal cannabis exposure were diagnosed with ASD, compared with a rate of 1.4% among all children. After adjusting for factors such as age, income, and other substance use, the investigators found that women who used cannabis during pregnancy had 1.5 times the risk of having a child with ASD. Cannabis use during pregnancy was also associated with 1.1 times the risk of an ADHD diagnosis and 1.2 times the risk of intellectual disability or a learning disorder, but these risks were not statistically significant after adjusting for other variables.

“Although findings of an increased risk for childhood neurodevelopmental disorders are of substantive interest, we emphasize a cautious interpretation,” Corsi and colleagues wrote. They noted that while their study factored in several important variables that are also associated with developmental risks (such as prenatal exposure to substances other than cannabis), there may be other contributing factors they overlooked.

For related information, see the Psychiatric News article “Cannabis Use During Pregnancy on the Rise.”