Objective: To describe prevalent patterns of co-use of alcohol, tobacco, and licit and illicit controlled substances, and examine sociodemographic and clinical correlates of co-use, in a nationally representative sample of women of reproductive age.

Methods: We analyzed data from pregnant and non-pregnant women 18-49 years of age who responded to the National Survey on Drug Use and Health (NSDUH) from 2015-2017. Weighted proportions and corresponding 95% confidence intervals (95% CI) were used to report differences in past-month substance use patterns (no use, single use, co-use) in both groups. Weighted crude and multivariate adjusted logistic regression models were used to assess the association between population characteristics and the type of substance use pattern in pregnant and non-pregnant women.

Results: Between 2015-2017, overall prevalence of past-month substance co-use among pregnant women was 6.4% and among non-pregnant women was 23.0%. Nearly all of the most frequent co-use patterns included combinations of alcohol, tobacco, and marijuana. Determinants of co-use among pregnant women included: African-American/Black race compared to white [AOR (95% CI): 2.19 (1.09, 4.41)] and past year alcohol or substance abuse/dependence [AOR: 2.65 (1.37, 5.14)]. Individuals in the middle-income group ($30,000-50,000 USD annually) [AOR: 0.45 (0.23, 0.91)] or in their second trimester of pregnancy [AOR: 0.42 (0.20, 0.86)] displayed lower odds of co-use compared to those in the lowest income category and those in the first trimester, respectively.

Conclusion: Use, misuse, and co-use of a health efforts that aim to improve maternal and child health should address the complexities of substance use patterns during pregnancy, including and especially of tobacco, alcohol, and marijuana.