Prenatal cannabis use disorder and future risk of road traffic injuries in Canadian children.

The extent to which child traffic injuries may be attributed to parents who use cannabis before driving is unknown. We investigated whether prenatal cannabis use disorders may predict future road traffic injuries in children. We conducted a cohort study of 792,082 children in Quebec, Canada with 6,280,663 years of follow-up between 2006 and 2019. The main exposure measure was maternal cannabis use disorder before or during pregnancy. The main outcome measure was future hospitalizations for transport-related injuries in children after birth. Using Cox proportional hazards regression models adjusted for potential confounders, we estimated hazard ratios and 95% confidence intervals (CI) for the association of prenatal cannabis use disorders with transport-related injuries in children. Maternal cannabis use disorders before birth were associated with 5.64 times the risk of hospitalization for future motor vehicle crash injuries in children (95% CI 2.61-12.21). The risk increased with the child's age. Prenatal cocaine, opioid, and other drug use disorders were not associated with pediatric transport-related injuries. Maternal cannabis use disorders before birth may be an early predictor of childhood injuries from motor vehicle crashes.