Question and Methods: This multi-centre, randomized, double blind, placebo-controlled trial compares spontaneous passage of gestational sac in patients with US-confirmed missed miscarriage when treated with mifepristone + misoprostol or placebo + misoprostol.
Findings: The primary outcome of failure to pass gestational sac within 7 days was 17% in mifepristone + misoprostol versus 24% in placebo + misoprostol. ARR = 6.6% and NNT = 15.
Limitations: Regulatory burdens in Ontario mean that the treatment is only covered for medical abortions and the use for missed miscarriage is costly to patients at $337 for patients.
Interpretation: This large RCT shows a significant reduction in failure to pass gestational sac when treated with mifepristone + misoprostol for missed miscarriage up to 14 weeks gestation compared to misoprostol alone. It adds to the body of evidence that this is a safe and effective treatment with missed miscarriage.