Objective: The objective of the study was to provide national prevalence, patterns, and correlates of marijuana use in the past month and past 2-12 months among women of reproductive age by pregnancy status.

Study design: Data from 2007-2012 National Surveys on Drug Use and Health, a cross-sectional nationally representative survey, identified pregnant (n = 4971) and nonpregnant (n = 88,402) women 18-44 years of age. Women self-reported marijuana use in the past month and past 2-12 months (use in the past year but not in the past month). χ(2) statistics and adjusted prevalence ratios were estimated using a weighting variable to account for the complex survey design and probability of sampling.

Results: Among pregnant women and nonpregnant women, respectively, 3.9% (95% confidence interval [CI], 3.2-4.7) and 7.6% (95% CI, 7.3-7.9) used marijuana in the past month and 7.0% (95% CI, 6.0-8.2) and 6.4% (95% CI, 6.2-6.6) used in the past 2-12 months. Among past-year marijuana users (n = 17,934), use almost daily was reported by 16.2% of pregnant and 12.8% of nonpregnant women; and 18.1% of pregnant and 11.4% of nonpregnant women met criteria for abuse and/or dependence. Approximately 70% of both pregnant and nonpregnant women believe there is slight or no risk of harm from using marijuana once or twice a week. Smokers of tobacco, alcohol users, and other illicit drug users were 2-3 times more likely to use marijuana in the past year than respective nonusers, adjusting for sociodemographic characteristics.

Conclusion: More than 1 in 10 pregnant and nonpregnant women reported using marijuana in the past 12 months. A considerable percentage of women who used marijuana in the past year were daily users, met abuse and/or dependence criteria, and were polysubstance users. Comprehensive screening, treatment for use of multiple substances, and additional research and patient education on the possible harms of marijuana use are needed for all women of reproductive age.