Association between marijuana use and adverse obstetrical and neonatal outcomes.

OBJECTIVE: To evaluate associations between marijuana exposure and adverse outcomes excluding women with polysubstance abuse and stratifying for concurrent maternal tobacco use.

STUDY DESIGN: We performed a retrospective cohort study evaluating various obstetrical and neonatal outcomes including: preterm delivery, pre-eclampsia, gestational diabetes, cesarean delivery, fetal growth restriction, a composite which included stillbirth or neonatal intensive care unit admission, and perinatal mortality. We stratified study groups according to the maternal tobacco use and performed a logistic regression analysis.

RESULTS: We included 6468 women, 6107 nonusers and 361 marijuana users. After adjustment for maternal age, race, parity, body mass index and no prenatal care, we found higher rates of small for gestational age (aOR 1.30 (95% CI 1.03 to 1.62)) and neonatal intensive care unit admission (aOR 1.54 (1.14 to 2.07)) in women who were not tobacco users. Other obstetrical outcomes including preterm delivery and fetal anomalies were not increased with maternal marijuana use.

CONCLUSION: Maternal marijuana use does not increase the risk of adverse obstetrical outcomes or fetal anomalies, but does increase the risk for small for gestational age and neonatal intensive care unit admission.