Cannabis legalization and cannabis-involved pregnancy hospitalizations in Colorado

The primary objective of this study was to evaluate the association between presence of recreational cannabis dispensaries and prevalence of cannabis-involved pregnancy hospitalizations in Colorado. This was a retrospective cohort study of pregnancy-related hospitalizations co-coded with cannabis diagnosis codes in the Colorado Hospital Association from January 1, 2011, through December 31, 2018 (recreational cannabis began January 1, 2014). Our primary outcome was cannabis-involved pregnancy hospitalizations per 10 k live births per county. The primary exposure measure was county variation in the number of recreational dispensaries. We controlled for counties' baseline exposure to medical cannabis dispensaries and used Poisson regression to evaluate the association between exposure to recreational cannabis and hospitalizations. During the study period, cannabis-involved pregnancy hospitalizations increased from 429 to 1210. Mean hospitalizations per county (1.7 to 4.7) and per 10 k live births (13.2 to 55.7) increased. Overall, increasing recreational dispensaries were associated with increases in hospitalizations (1.02, CI: 1.00,1.04). When comparing counties with different densities of baseline medical cannabis market, low and high exposure counties had fewer hospitalizations than those counties with no exposure (low: IRR 0.97, CI: 0.96-0.99; high: 0.98, CI: 0.96-0.99). In Colorado, there was more than a two-fold increase in cannabis-involved pregnancy hospitalizations between 2011 and 2018. Counties with no baseline exposure to medical cannabis had a greater increase than other counties, suggesting the recreational market may influence cannabis use among pregnant individuals.