UC Davis

To summarize clinical outcomes and adverse effects of medical abortion regimens consisting of mifepristone followed by buccal misoprostol in pregnancies through 70 days of gestation.

We used PubMed, ClinicalTrials.gov, and reference lists from published reports to identify relevant studies published between November 2005 and January 2015 using the search terms "mifepristone and medical abortion" and "buccal and misoprostol."

Studies were included if they presented clinical outcomes of medical abortion using mifepristone and buccal misoprostol through 70 days of gestation. Studies with duplicate data were excluded.

We included 20 studies with a total of 33,846 women through 70 days of gestation. We abstracted efficacy and ongoing pregnancy rates as an overall rate and by gestational age in days in reference to completed weeks (eg, 49 days or less, 50-56 days, 57-63 days, 64-70 days) and adverse effects when reported. The overall efficacy of mifepristone followed by buccal misoprostol is 96.7% (95% confidence interval [CI] 96.5-96.8%) and the continuing pregnancy rate is 0.8% (95% CI 0.7-0.9%) in approximately 33,000 pregnancies through 63 days of gestation. Only 332 women with pregnancies between 64 and 70 days of gestation are reported in the literature with an overall efficacy of 93.1% (95% CI 89.6-95.5%) and a continuing pregnancy rate of 2.9% (95% CI 1.4-5.7%). Currently available data suggest that regimens with a 24-hour time interval between mifepristone and buccal misoprostol administration are slightly less effective than those with a 24- to 48-hour interval. Rates of surgical evacuation for reasons other than ongoing pregnancy range from 1.8% to 4.2%. Severe adverse events like blood transfusion (0.03-0.6%) and hospitalization (0.04-0.9%) are uncommon.

Outpatient medical abortion regimens with mifepristone followed in 24-48 hours by buccal misoprostol are highly effective for pregnancy termination through 63 days of gestation. More data are needed to evaluate clinical outcomes with regimens containing mifepristone followed in 24 hours by buccal misoprostol and in pregnancies beyond 63 days of gestation.