By Dr. Liji Thomas, MDReviewed by Benedette Cuffari, M.Sc.Mar 11 2025

New research reveals a threefold rise in disruptive behavior disorders among children exposed to maternal cannabis use during pregnancy and postpartum.

Study: Maternal cannabis use disorder and offspring behavioral outcomes: findings from a linked data cohort study. Image Credit: Sebastian Duda / Shutterstock.com

In a recent study published in Psychiatry Research, researchers determine how maternal cannabis use disorder during and after pregnancy impacts the child’s behavior.

Maternal cannabis use and childhood behavioral disorders

Despite widespread cannabis use, particularly after the legalization of this substance throughout many states in the U.S., few studies have examined the impact of prolonged maternal cannabis use on disruptive behavior in children born to these mothers.

Disruptive behaviour disorders (DBDs), which are frequently encountered psychiatric issues in children, can be further categorized as conduct disorders (CDs) and oppositional defiant disorders (ODDs). Whereas ODD can lead to increased negative emotions like anger, resent, and blame, children with CD are more likely to be physically aggressive.

Over the past several decades, the prevalence of DBDs has increased, with males at a 2.5 times greater risk of these behavioral issues than female children. Simultaneously, maternal cannabis use disorder (CUD) cases have also risen over the past 20 years, particularly among pregnant women, with a prevalence rate rising from 1.01% to 9.8% during this period.

About the study

Data from over 222,600 mother-child dyads in the New South Wales region of Australia were obtained between January 1, 2003, and December 31, 2005. All mothers were diagnosed with CUD during pregnancy and postpartum, whereas mothers without CUD were included as controls.

All children were monitored from birth until December 2018 up to 15 years of age. DBD diagnoses were based on hospital admission and outpatient visit data, which characterized children as having ODD or CD according to the International Statistical Classification of Diseases and Related Health Problems, 10^th Revision, Australian Modification (ICD-10-AM).

Study findings

A total of 1,003 children were diagnosed with DBDs, 70% of whom were male. About 3.4% of children with DBDs were born to mothers diagnosed with CUD during pregnancy as compared to 0.8% of whom were born to mothers with postpartum CUD. Approximately 4% of children with DBDs were born to mothers with perinatal CUD.

About 30% of children diagnosed with DBD were from the lowest socioeconomic category, whereas 31% were exposed to maternal smoking during pregnancy. Among children diagnosed with DBDs, 9.7% were born pre-term, 6.9% were low birth weight, whereas 0.5% and 2.4% were born to mothers who used tobacco during pregnancy and were diagnosed with depressive disorders, respectively.

After adjusting for other risk factors, including maternal smoking, a 3.6-fold increased risk of DBD was observed among children exposed to chronic cannabis use during pregnancy. Maternal use of other substances led to a similarly increased risk of DBDs in children born to these mothers, with maternal opioid use disorder leading to a 2.96-fold greater risk of these children being diagnosed with DBDs.

CUD may affect the fetus and newborn through cannabinoids, particularly Δ9-tetrahydrocannabinol (THC), carried in blood and breast milk. Exposure to THC has the potential to alter genes that are involved in neurotransmitter release and neurological development.

Exposure to cannabis during pregnancy, perinatal, and postnatal periods could influence the fundamental brain developmental processes, thereby increasing the risk of behavioral disorders in exposed offpspring.”

Conclusions

The study findings suggest that CUD among pregnant women independently increases the risk of DBDs in both male and female children by threefold. This increased risk was not affected by other factors like maternal drinking or smoking during pregnancy, low socioeconomic status, or maternal mental health disorders.

These observations should be interpreted cautiously, as paternal substance use and mental health histories were not included in the analysis, which can also impact the risk of DBD in children. The researchers of the current study also did not consider certain genetic factors, such as polygenetic risk scores (PRSs), which may also increase the risk of behavioral disorders in children.

Nevertheless, the results of the current study highlight the urgent need for public health strategies to mitigate the potential adverse effects associated with maternal cannabis use.