Maternal marijuana use and neonatal morbidity

Marijuana use is becoming increasingly common in the obstetric population; however, it is unknown whether it is associated with poor neonatal outcomes. We sought to determine the prevalence and risk factors for marijuana use in pregnancy and to evaluate whether marijuana use is independently associated with poor neonatal outcomes.

This was a retrospective cohort study of all consecutive, nonanomalous, term deliveries at 1 institution over a 4-year study period. Women with marijuana use during pregnancy, either by self-report or positive urine drug screen, were compared with women who did not use marijuana. The primary outcome was a composite neonatal morbidity including birthweight less than 2500 g, neonatal intensive care unit admission, 5-minute Apgar score less than 7, and umbilical artery pH less than 7.10. Univariate, bivariate, and multiple logistic regression analyses were performed.

Among the 8138 women in the cohort, 680 (8.4%) used marijuana during pregnancy. Women who used marijuana were younger; more likely to be of African American race; have inadequate prenatal care; and use tobacco, alcohol, and other drugs. Medical comorbidities did not differ between groups. After adjusting for smoking, other drug use, and African American race, the composite and all individual markers of poor neonatal outcome were not significantly higher among women who used marijuana during pregnancy.

Marijuana use is common in pregnancy but may not be an independent risk factor for poor neonatal outcomes in term pregnancies.