Prenatal cannabis use disorder and postpartum psychiatric emergency department visits: A retrospective cohort study of trends and associations in California, 2016-2021.

PURPOSE: Cannabis is the most-used substance during pregnancy and has known associations with psychiatric disorders (e.g., psychosis, depression). No prospective studies, however, have investigated associations between prenatal cannabis use disorder (CUD) and psychiatric outcomes in perinatal populations. METHODS: Annual cohorts of women with a live infant delivery in California from 2016 to 2021 were constructed using statewide linked hospital and emergency department (ED) discharge data. We examined temporal trends in prenatal CUD prevalence and compared risk of postpartum psychiatric ED visits between delivering women with prenatal CUD, prenatal alcohol use disorder (AUD; included as a benchmark exposure), and neither disorder. RESULTS: The study sample included 2,036,016 delivering women. Between 2016 and 2021, prenatal CUD prevalence increased 1.0% to 1.4%. Postpartum psychiatric ED visits occurred in 10.4% of women diagnosed with CUD, 15.6% with AUD, and 2.7% with neither diagnosis. Relative to women with neither, those with CUD had ~40% higher risk of any postpartum psychiatric ED visit (RRadj=1.39, 95% CI: 1.32-1.47), while AUD was associated with 80% increased risk (RRadj=1.80, 95% CI: 1.56-2.09). CONCLUSION: Elevated risk of adverse psychiatric outcomes associated with CUD underscore the need for consistent screening, diagnosis, and treatment among perinatal women with CUD diagnoses.