Acute care related to cannabis use during pregnancy after the legalization of nonmedical cannabis in Ontario

Abstract

Background: Cannabis use during pregnancy is increasing, but the contribution of cannabis legalization to these trends is unclear. We sought to determine whether health service utilization related to cannabis use during pregnancy increased after the legalization of nonmedical cannabis in October 2018 in Ontario, Canada. Methods: In this population-based, repeated cross-sectional study, we evaluated changes in the number of pregnant people who received acute care (emergency department visit or admission to hospital) between January 2015 and July 2021 among all people eligible for the province’s public health coverage. We used segmented regression to compare changes in the quarterly rate of pregnant people with acute care related to cannabis use (primary outcome) with the quarterly rates of acute care for mental health conditions or for noncannabis substance use (control conditions). We identified risk factors associated with acute care for cannabis use and the risk of adverse neonatal outcomes using multivariable logistic regression models. Results: The mean quarterly rate of acute care for cannabis use during pregnancy increased from 11.0 per 100 000 pregnancies before legalization to 20.0 per 100 000 pregnancies after legalization (incidence rate ratio [IRR] 1.82, 95% confidence interval [CI] 1.44–2.31), while acute care for mental health conditions decreased (IRR 0.86, 95% CI 0.78–0.95) and acute care for noncannabis substance use did not change (IRR 1.03, 95% CI 0.91–1.17). Legalization was not associated with an immediate change, but the quarterly change in rates of pregnancies with acute care for cannabis use increased by 1.13 (95% CI 0.46–1.79) per 100 000 pregnancies after legalization. Pregnant people with acute care for cannabis use had greater odds of having received acute care for hyperemesis gravidarum during their pregnancy than those without acute care for cannabis use (30.9% v. 2.5%, adjusted odds ratio [OR] 9.73, 95% CI 8.01–11.82). Pregnancies with acute care for cannabis use had greater odds of newborns being born preterm (16.9% v. 7.2%, adjusted OR 1.93, 95% CI 1.45–2.56) and of requiring care in the neonatal intensive care unit (31.5% v. 13.0%, adjusted OR 1.94 95% CI 1.54–2.44) than those without acute care for cannabis use. Interpretation: The rate of acute care related to cannabis use during pregnancy almost doubled after legalization of nonmedical cannabis, although absolute increases were small. These findings highlight the need to consider interventions to reduce cannabis use during pregnancy in jurisdictions pursuing legalization.

The impact of recreational cannabinoid legalization on utilization in a pregnant population

“…The results of this study did not support our hypothesis that cannabinoid use would increase during the post-legalization period; rather, there was a statistically significant decrease in observed utilization. This is inconsistent with other studies which have found increased rates of cannabinoid use in both the general population ( 15 , 47 , 48 ) and specifically during the pre-conception, prenatal, and post-partum time periods ( 16 , 17 ) following the legalization period in other states. This trend of increased use of cannabinoid products during pregnancy has also been shown in other countries including Canada ( 17 ).…”

“…This is inconsistent with other studies which have found increased rates of cannabinoid use in both the general population ( 15 , 47 , 48 ) and specifically during the pre-conception, prenatal, and post-partum time periods ( 16 , 17 ) following the legalization period in other states. This trend of increased use of cannabinoid products during pregnancy has also been shown in other countries including Canada ( 17 ).…”

“…This also translates to pregnancy, where cannabinoid products remain the most used illicit substance in pregnancy (10). The impacts of legalizing cannabinoid products have been a controversial and pressing public health concern, and many studies show an increase in utilization after legalization (15)(16)(17). One study in particular analyzed data from six states that legalized cannabinoid products and the analysis revealed an increase in utilization in pregnant individuals throughout the preconception, prenatal, and postpartum stages (16).…”

TheCannabis Act: implications for human participant research with cannabis

“…[9][10][11][12] An increase in cannabis-induced psychosis in young adults (older than 19 yr) has been reported in some 13 but not all studies, 14 and the number of pregnant women needing hospital care for cannabis-related problems has doubled. 15 Additionally, studies have shown an increase in injured drivers who used cannabis. 16 These findings primarily reflect periods with immature cannabis markets and coincide with the COVID-19 pandemic, complicating the assessment of Bill C-45's impact.…”