Maternal cannabis use during pregnancy is associated with abnormal placental dysfunction in a multicenter cohort study. “Ongoing cannabis exposure beyond the first trimester was associated with higher risk of the primary composite outcome, and a dose response was noted with higher odds of the primary composite outcome with higher mean cumulative amounts of cannabis metabolite in urine specimens across the duration of the pregnancy,” the authors conclude.
The Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be cohort ran from 2010 through 2013. Stored urine samples and abstracted pregnancy outcome data were analyzed in June 20202 through Apr. 2023. Samples were tested using urine immunoassay for 11-nor-9-carboxy-Δ9-tetrahydrocannabinol. Cannabis exposure was defined as only during the first trimester or ongoing exposure after that. The dichotomous primary composite outcome included small-for-gestational-age birth, medically indicated preterm birth, stillbirth, or hypertensive disorders of pregnancy.
“Of 10,038 participants, 9,257 were eligible for this analysis,” the authors write. “Of the 610 participants (6.6%) with cannabis use, 32.4% (n = 197) had cannabis exposure only during the first trimester and 67.6% (n = 413) had ongoing exposure beyond the first trimester. Cannabis exposure was associated with the primary composite outcome (25.9% in the cannabis exposure group vs 17.4% in the no exposure group; adjusted relative risk, 1.27 [95% CI, 1.07-1.49]) in the propensity score–weighted analyses after adjustment for sociodemographic characteristics, body mass index, medical comorbidities, and active nicotine use ascertained via urine cotinine assays. In a 3-category cannabis exposure model (no exposure, exposure only during the first trimester, or ongoing exposure), cannabis use during the first trimester only was not associated with the primary composite outcome; however, ongoing cannabis use was associated with the primary composite outcome (adjusted relative risk, 1.32 [95% CI, 1.09-1.60]).”