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

De Alba L.; Margerison C.; Gemmill A.; Goldman-Mellor S. · Annals of epidemiology · 2026

**Background & Methods** This retrospective cohort study analyzed statewide linked hospital and emergency department discharge data from California (2016-2021) to examine temporal trends in prenatal cannabis use disorder (CUD) prevalence and associated postpartum psychiatric outcomes. The study population included 2,036,016 delivering women, with comparisons made between those with prenatal CUD, prenatal alcohol use disorder (AUD), and neither diagnosis. **Key Findings** • Prenatal CUD prevalence increased from 1.0% in 2016 to 1.4% in 2021, establishing cannabis as the most-used substance during pregnancy in the study population. • Postpartum psychiatric emergency department visits occurred in 10.4% of women with CUD compared to 2.7% without either CUD or AUD, representing a 39% increased risk (RRadj=1.39, 95% CI: 1.32-1.47) relative to unexposed women. • Women with prenatal AUD demonstrated higher psychiatric ED visit rates (15.6%), with an 80% increased risk (RRadj=1.80, 95% CI: 1.56-2.09), suggesting CUD carries measurable but somewhat lower psychiatric risk than AUD in the postpartum period. **Dosage & Administration** Not reported. **Safety & Adverse Effects** The study identified elevated risk of postpartum psychiatric emergency department visits as the primary adverse outcome associated with prenatal CUD. Specific psychiatric diagnoses and symptoms documented during ED visits were not detailed in the abstract. The authors noted known associations between cannabis use and psychiatric disorders including psychosis and depression, though the mechanism linking prenatal CUD to postpartum psychiatric emergencies was not elucidated. **Evidence Quality** This retrospective cohort study provides observational evidence without randomization or prospective design. The authors acknowledge this is the first study examining prenatal CUD associations with perinatal psychiatric outcomes, filling a research gap. Limitations include reliance on administrative discharge data dependent on documented diagnoses, inability to assess unmeasured confounders (socioeconomic status, psychiatric history), and lack of data on cannabis dosage, frequency, or trimester of use. The study provides population-level trends but cannot establish causality. Large sample size and statewide administrative data enhance generalizability within California, though applicability to other regions requires consideration.

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