Cannabis Use During Pregnancy Linked to Increased Risks of preterm birth, SGA, and LBW: JAMA

A new study published in the Journal of American Medical Association showed that even after controlling for tobacco co-use, cannabis use during pregnancy was linked to increased risks of short for gestational age (SGA), low birth weight (LBW), and preterm delivery (PTB). Confidence in these findings has strengthened from low to moderate based on updated meta-analysis, offering important insights for patient counseling and public health policy development.

The rate of cannabis usage during pregnancy has more than doubled over the last 20 years. Also, the most widely used federally prohibited substance during pregnancy is cannabis. There is reason for concern since THC, the primary psychoactive ingredient in cannabis, can cross the placenta and attach to endocannabinoid receptors on important embryonic organs. However, due in part to the few and conflicting information that is currently available, doctors are not routinely counseling patients regarding cannabis use during pregnancy.

Cannabis is still the most widely used illicit drug during pregnancy, and its usage during pregnancy is on the rise. There is growing evidence that cannabis usage during pregnancy may have a negative impact on the health of the fetus and newborn. In order to give a contemporary understanding of cannabis usage during pregnancy and the effects for fetuses and newborns, Jamie Lo and team carried this study to update a living systematic review and meta-analysis.

The bibliographic databases Global Health, MEDLINE, PsycInfo, CINAHL, and Evidence-Based Medicine Reviews Cochrane Database of Systematic Reviews were searched from November 1, 2021, to April 4, 2024, to update the prior review. Included were cohort or case-control studies that examined the effects of cannabis use during pregnancy on certain fetal or neonatal outcomes, controlling for confounders such as co-use of tobacco products.

A total of 51 studies were synthesized for this update, including 8 new studies with 1,709,998 individuals (N = 21 146,938). Cannabis use during pregnancy was linked to higher odds of LBW, PTB, and SGA, according to moderate-certainty evidence derived from meta-analyses of adjusted effect sizes, and to higher odds of perinatal death, according to low-certainty evidence.

The evidence was previously assessed as low certainty or extremely low. Overall, even after controlling for co-use of tobacco products, cannabis use during pregnancy was linked to higher risks of PTB, SGA, and LBW.

Source:

Lo, J. O., Ayers, C. K., Yeddala, S., Shaw, B., Robalino, S., Ward, R., & Kansagara, D. (2025). Prenatal cannabis use and neonatal outcomes: A systematic review and meta-analysis. JAMA Pediatrics. https://doi.org/10.1001/jamapediatrics.2025.0689