Association of Mandatory Warning Signs for Cannabis Use During Pregnancy With Cannabis Use Beliefs and Behaviors

IMPORTANCE: As states have legalized recreational cannabis use, some have enacted policies mandating point-of-sale warning signs with information on harms of using cannabis during pregnancy. While research has found such warning signs are associated with increased adverse birth outcomes, reasons why are unclear. OBJECTIVE: To examine whether exposure to cannabis warning signs is associated with cannabis-related beliefs, stigma, and use. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used data from a population-based online survey conducted from May to June 2022. Participants included pregnant and recently pregnant (within past 2 years) members of the national probability KnowledgePanel and nonprobability samples in all US states and Washington, the District of Columbia, where recreational cannabis is legal. Data were analyzed from July 2022 to April 2023. EXPOSURE: Living in 1 of 5 states with a warning signs policy. MAIN OUTCOMES AND MEASURES: Outcomes of interest were self-reported beliefs (linear) that cannabis use during pregnancy is not safe, should be punished, and is stigmatized and cannabis use during pregnancy (dichotomous). Regressions, accounting for survey weights and clustering by state, examined associations of warning signs with cannabis-related beliefs and use. RESULTS: A total of 2063 pregnant or recently pregnant people (mean [SD] weighted age, 32 [6] years) completed the survey, and 585 participants (weighted, 17%) reported using cannabis during their pregnancy. Among people who used cannabis during their pregnancy, living in a warning signs state was associated with beliefs that cannabis use during pregnancy was safe (β = −0.33 [95% CI, −0.60 to −0.07]) and that people who used cannabis during pregnancy should not be punished (β = −0.40 [95% CI, −0.73 to −0.07]). Among people who did not use cannabis before or during pregnancy, living in a warning signs state was associated with beliefs that use was not safe (β = 0.34 [95% CI, 0.17 to 0.51]), that people should be punished for use (β = 0.35 [95% CI, 0.24 to 0.47]), and that use was stigmatized (β = 0.35 [95% CI, 0.07 to 0.63]). Warning signs policies were not associated with use (adjusted odds ratio, 1.11 [95% CI, 0.22 to 5.67]). CONCLUSIONS AND RELEVANCE: In this cross-sectional study of warning signs and cannabis-related use and beliefs, warning signs policies were not associated with reduced cannabis use during pregnancy or with people who used cannabis believing use during pregnancy was less safe but were associated with greater support for punishment and stigma among people who did not use cannabis.