Abortion Safety and the Use of Mifepristone as Typically Prescribed in Canada

December 8, 2021.

DOI: 10.1056 / NEJMsa2109779

Commentary

This study used population-based administrative data from Ontario, Canada, to provide a comparative analysis of incidence trends before mifepristone became available (January 2012 to December 2016) and after it became available without restrictions. (November 7, 2017 to March 15, 2020)

The results showed that a total of 195,183 abortions were performed before Mifepristone was made available and 84,032 abortions were performed after it was made available without restrictions. This shows a decrease in the abortion rate with regular prescriptions, but more slowly than predicted compared to the trend before Mifepristone became available. (Risk difference adjusted for time series analysis, 1.2 49 years per 1,000 residents of 15 women; 95% confidence interval [CI], 1.1 to 1.4)

In contrast, the proportion of abortions provided as a medical procedure increased from 2.2% to 31.4%. (Adjusted risk difference, 28.8 percentage points; 95% CI, 28.0 to 29.7)

There was no change in the incidence of serious adverse events between the period before mifepristone became available and the unrestricted period.

Based on these analyses, it appears that the impact of mifepristone becoming available as a regular prescription has resulted in relatively stable miscarriage rates, a rapid increase in the rate of medication-induced miscarriages, and stable adverse events and complications. (The study was funded by the Canadian Institutes of Health Research and the Institute of Women's Health.)