Changes in the rate of acute care for cannabis use and control conditions during pregnancy before and after the legalization of nonmedical cannabis in Ontario, Canada
| Condition | Before legalization* | After legalization* | Incidence rate ratio (95% CI) | ||
|---|---|---|---|---|---|
| No. of pregnancies | Mean quarterly rate per 100 000 pregnancies | No. of pregnancies | Mean quarterly rate per 100 000 pregnancies | ||
| Cannabis use | 299 | 11.0 | 241 | 20.0 | 1.82 (1.44–2.31) |
| Noncannabis substance use | 1231 | 41.4 | 575 | 42.8 | 1.03 (0.91–1.17) |
| Any mental health condition | 4575 | 189.1 | 1880 | 162.8 | 0.86 (0.78–0.95) |
Note: CI = confidence interval.
↵* Total of 678 353 pregnancies before legalization and 302 045 pregnancies after legalization.