A comprehensive study of over 222,000 pregnancies has found that maternal cannabis use significantly increases the risk of children developing serious behavioral problems, adding to mounting evidence against marijuana use during pregnancy.
Women who used cannabis during pregnancy were 3.5 times more likely to have children with disruptive behavioral disorders, according to research recently published in the journal Psychiatry Research. Even postnatal cannabis use raised the risk by nearly threefold.
"Cannabinoid ingredients can cross the placenta and enter breast milk, potentially affecting brain development," explained senior researcher Rosa Alati, head of population health at Curtin University in Australia. "This research provides critical evidence to help shape health policies aimed at minimizing harm."
Specific Behavioral Impacts Identified
The Australian study tracked children born between 2003 and 2005 in New South Wales, comparing developmental outcomes between those exposed to cannabis prenatally and those who were not. Researchers found that children of mothers with cannabis use disorder showed significantly higher rates of specific behavioral issues.
"We found children of mothers with cannabis use disorder were at a significantly higher risk of developing behavioral issues such as oppositional defiant disorder and conduct disorder," said lead researcher Abay Tadesse, a doctoral student at Curtin University.
These behavioral problems manifested as hostility toward authority figures, disobedience, and aggressive behavior toward others—issues that can significantly impact a child's social development and academic performance.
Confirming Previous Research
The findings align with earlier studies linking prenatal cannabis exposure to developmental problems. An October 2024 study published in JAMA Pediatrics connected cannabis exposure in the womb to poorer cognitive function, including difficulties with impulse control and attention, as well as increased aggressive behavior.
This growing body of evidence is particularly concerning as cannabis use during pregnancy has increased in recent years, with some women turning to it to manage pregnancy-related issues like nausea, sleep problems, and stress.
Clinical Implications
Despite cannabis being marketed as a "natural" remedy for pregnancy discomforts, healthcare professionals emphasize that natural doesn't mean safe for fetal development.
"Although cannabis is a natural product, there are still many risks to using it during pregnancy," noted Sarah Keim, principal investigator in the Center for Biobehavioral Health at Nationwide Children's Hospital, who led a separate study on the topic. "Consulting with a healthcare provider to find safer options to help with these issues during pregnancy is important."
The research is especially relevant given the increasing potency of cannabis products available today compared to decades past, potentially amplifying developmental risks.
Long-term Consequences
The behavioral disorders linked to prenatal cannabis exposure—including oppositional defiant disorder and conduct disorder—can have lasting impacts on children's development and future prospects. These conditions often require specialized interventions and can affect educational outcomes and social relationships.
Researchers emphasize that more studies are needed to fully understand the mechanisms by which cannabis affects fetal brain development and to identify potential protective factors or interventions that might mitigate these risks.
For now, the evidence strongly suggests that women should avoid cannabis use both during pregnancy and while breastfeeding to protect their children's neurological development and future behavioral health.
Healthcare providers are encouraged to screen for cannabis use during prenatal care and provide education about these risks, along with offering evidence-based alternatives for managing pregnancy-related discomforts.
