Birth outcomes associated with cannabis use before and during pregnancy

INTRODUCTION: This study aimed to examine the association between cannabis use before and during pregnancy and birth outcomes. RESULTS: Overall, 26.3% of women reported previous use of cannabis and 2.6% reported current use. Multivariate analysis, controlling for potential confounders, including tobacco smoking, alcohol consumption, and use of other illicit drugs, showed that cannabis use in pregnancy was associated with low birth weight (odds ratio (OR) = 1.7; 95% confidence interval (CI): 1.3-2.2), preterm labor (OR = 1.5; 95% CI: 1.1-1.9), small for gestational age (OR = 2.2; 95% CI: 1.8-2.7), and admission to the neonatal intensive care unit (OR = 2.0; 95% CI: 1.7-2.4). DISCUSSION: The results of this study show that the use of cannabis in pregnancy is associated with increased risk of adverse birth outcomes. Prevention programs that address cannabis use during pregnancy are needed. METHODS: Data were from women birthing at the Mater Mothers' Hospital in Brisbane, Australia, over a 7-y period (2000-2006). Women were interviewed in the initial antenatal visit about their use of cannabis and other substances. Records for 24,874 women who provided information about cannabis use, and for whom birth outcomes data were available, were included in the analysis.