Written by Kimiko Dunbar
Spoon Feed
Prenatal cannabis use is associated with increased odds of low birth weight, preterm birth, SGA, and perinatal mortality, even after adjusting for concurrent tobacco use.
A budding public health problem
Cannabis use in pregnancy has increased dramatically in the past 20 years. Cannabis can cross the placenta and bind to endocannabinoid receptors on fetal organs, causing risk for the developing fetus. Data regarding the impact of cannabis use on fetal outcomes is limited; many prior studies are confounded by polysubstance use. This systematic review and meta-analysis of cohort or case-control studies that adjusted for confounders such as concurrent tobacco use examined whether prenatal cannabis use affects neonatal outcomes. Across 51 studies (N=21 million), cannabis exposure during pregnancy was associated with increased odds of low birth weight (OR 1.75), preterm birth (OR 1.52), small for gestational age (OR 1.57), and perinatal mortality (OR 1.29). This study is limited by heterogeneity in literature and unclear specifics about cannabis exposure (frequency, administration route, dose). Overall, findings support counseling against prenatal cannabis use due to elevated neonatal risks.
How does this change my practice?
In my personal experience, the legalization of cannabis has created a false perception of safety, increasing use during pregnancy and continued use while breastfeeding. Conversations regarding cessation during pregnancy or after birth can be challenging, especially in instances where patients report relief of common pregnancy symptoms, i.e. nausea. We need public health initiatives and more research on the impact of continued use while breastfeeding. In the meantime, I’ll continue to counsel on the risks of cannabis exposure and will have more data to back myself up when I do.
Source
Prenatal Cannabis Use and Neonatal Outcomes: A Systematic Review and Meta-Analysis. JAMA Pediatr. 2025 May 5:e250689. doi: 10.1001/jamapediatrics.2025.0689. Epub ahead of print. PMID: 40323610
