Impact of Recreational Cannabis Legalization on Disparities in Prenatal Cannabis Use

Background/Purpose: Cannabis use among pregnant women has increased more than 60% over the past decade during a time of increasing liberalization of cannabis policies. However, gaps remain in understanding the effects of legalization on prenatal cannabis use and whether they vary across groups. Using data on representative samples of new mothers, we examined the impact of recreational cannabis legalization on disparities in prenatal cannabis.

Methods: We used 2016-2021 data from the Pregnancy Risk Assessment Monitoring System (PRAMS), an annual survey administered by the Centers for Disease Control and Prevention (CDC) to samples of women who recently gave birth. The CDC uses the terms mothers and women in their PRAMS materials, so we have retained that language. Women self-reported whether they used cannabis at any point during pregnancy, which we dichotomized (yes/no). The effective date of recreational cannabis legalization was linked to the approximate time of conception, which was calculated as 9 months prior to the month/year of birth.

Using data on 94,347 women from 21 states and DC, we conducted fixed effects probit regression models to examine the impact of recreational cannabis legalization on prenatal cannabis use controlling for demographics (age, education, race and ethnicity, marital status, health insurance status, when prenatal care started, multiple birth, parity), other cannabis policies (medical cannabis legalization, cannabis decriminalization), year and state fixed effects. We included interactions to test for differential effects by demographic (age, education, race and ethnicity) and higher-risk (depressive symptoms pre-pregnancy, prenatal smoking) strata. We report average marginal effects.

Results: Overall, 5.8% of women reported prenatal cannabis use. Nine states and DC legalized recreational cannabis by 2021. Recreational cannabis legalization increased prenatal cannabis use by 2.13 percentage points (0.021; 95% CI 0.008, 0.034), with differential effects by race and ethnicity (p=0.02) and prenatal smoking (p=0.02). Recreational cannabis legalization increased use among White women by 2.57 percentage points (0.026; 95% CI 0.012, 0.040), but not among other racial and ethnic groups. Legalization also increased use among women who smoked prenatally by 9.90 percentage points (0.099; 95% CI 0.048, 0.150), but not non-smokers. There were trend interaction effects by education (p=0.07) and depressive symptoms (p=0.06), suggesting increased use post-legalization among women with less education and who reported depressive symptoms pre-pregnancy. There was no evidence of age interactions.

Conclusions and Implications: Our results indicate that recreational cannabis legalization had unintended consequences of increasing prenatal cannabis use, particularly among women who were White and from higher-risk groups. These findings suggest that recreational cannabis legalization should be paired with more targeted public health outreach and awareness, particularly towards people considering pregnancy and the public health community. We will further test spillover effects of legalization on other substances to better understand the broader effects of cannabis policies on pregnant people.