Prevalence and Perceived Financial Costs of Marijuana versus Tobacco use among Urban Low-Income Pregnant Women.

Objective: To examine the relative prevalence of marijuana and tobacco use among low-income post-partum women, using self-report, urine, and hair testing data; and to further explore perceptions of the substances among postpartum women by evaluating perceived risk and monetary cost of prenatal marijuana versus tobacco use.

Methods: Data from two studies were available for a total of 100 (Study 1) and 50 (Study 2) low-income, primarily African-American post-partum women. Study 1 participants completed brief self-report measures of substance use as well as urine and hair samples; study 2 participants completed a brief opinion survey regarding the risks and monetary costs of prenatal marijuana use.

Results: In Study 1, the self-reported prevalence of any tobacco or marijuana use in the past three months was 17% and 11%, respectively. However, objectively-defined marijuana use was more prevalent than self-reported tobacco use: 14% tested positive for marijuana by urinalysis, and 28% by hair analysis. Study 2 participants were more likely to believe that there is a safe level of marijuana use during pregnancy, and nearly half believed that using marijuana during pregnancy was less expensive than smoking cigarettes.

Conclusion: Marijuana use may be as or more prevalent than tobacco use among low-income, African-American pregnant women. These findings may in part be attributable to perceptions of roughly equivalent cost and the lack of a clear public health message regarding prenatal marijuana use, combined with growing pro-marijuana advocacy. A broader public health response to address prenatal marijuana use, along with other substances of abuse, is needed.