Cannabis Use in Pregnancy Linked to Autism

A study involving over 200,000 pregnant women and their children found significant associations between cannabis use disorder during pregnancy and an increased risk of neurodevelopmental disorders, including autism.

U.S. Centers for Disease Control and Prevention (CDC) estimates indicate that autism spectrum disorder (ASD) impacts one in 36 children in the United States. Moreover, recent data found that one in 10 American children have attention-deficit/hyperactivity disorder (ADHD).

Despite the increasing numbers, scientists have not identified what causes ASD or ADHD. However, some research suggests genetic factors or environmental exposures may play a role in these neurodevelopmental disorders.

Prenatal lifestyle factors, such as cannabis use, may also contribute to an increased risk of autism or ADHD. For example, animal studies have shown that using cannabis while pregnant may lead to brain changes in offspring associated with neurodevelopmental disorders.

Reports also suggest that women who use marijuana during pregnancy may experience unhealthy pregnancy outcomes, including having a baby with a low birth weight.

Moreover, a review of research published earlier this year found maternal prenatal marijuana exposure may be associated with a higher risk of ADHD and ASD.

Still, a 2023 study found that prenatal cannabis use did not predict ASD-related behaviors.

However, research presented on April 8 at the European Psychiatric Association (EPA) Congress 2024 paints a more concerning picture of the impacts of cannabis use during pregnancy and provides more evidence that prenatal marijuana use is not safe for an unborn child.

The observational study looked at data from over 200,000 mother-child pairs in Australia to determine whether prenatal exposure to marijuana due to cannabis use disorder (CUD) impacts neurodevelopmental outcomes in children.

Moreover, babies born to mothers with a history of smoking and cannabis use during pregnancy were at even higher risk of these neurodevelopmental disorders.

The scientists also found that prenatal CUD impacted other pregnancy outcomes, including preterm birth and low birth weight, which further increases the risks of ASD, ADHD, and ID.

In an EPA press release, senior study author Professor Rosa Alati, head of the Curtin School of Population Health, said, "These findings highlight the need to increase awareness of the risks associated with cannabis use during pregnancy among women planning to become pregnant."

The rising concern about prenatal marijuana use

According to Canadian research, 2% to 5% of pregnant women report using cannabis. However, other research found that around 14% of women report heavy cannabis use — one or more joints per day — during the first trimester.

CDC data shows that 4.2% of women in the U.S. use cannabis while pregnant. Still, marijuana use was self-reported, so the actual number of pregnant individuals using the drug may be higher.

With the legalization of the drug expanding and the stigma associated with cannabis dissipating, health officials are concerned about the potential for increased use among young women, particularly pregnant individuals.

"This study is unique because it utilizes linked data with confirmed diagnoses, providing a more robust picture of the potential risks associated with prenatal cannabis use," Dr. Julian Beezhold, Secretary General of the European Psychiatric Association, said. "The results underscore the need for public health education campaigns and clinical interventions to raise awareness about the potential risks of cannabis use during pregnancy and to support women in making informed decisions regarding their health and the well-being of their children."