Objective: To study the efficacy, safety, and acceptability of oral immediately swallowed and buccal misoprostol 800 mcg after mifepristone 200 mg for terminating pregnancy through 63 days since the last menstrual period (LMP).
Methods: This seven-site study randomly assigned 966 women seeking abortions to oral or buccal misoprostol 800 mcg 24-36 hours after mifepristone 200 mg with 7-14-day follow-up.
Results: Success rates in the oral and buccal groups were 91.3% (389 of 426) and 96.2% (405 of 421), respectively (P=.003; relative risk [RR] 0.95, 95% confidence interval [CI] 0.92-0.98). Ongoing pregnancy occurred in 3.5% (15 of 426) of women who took oral misoprostol compared with 1.0% (4 of 421) of women in the buccal group (P=.012; RR 3.71, 95% CI 1.24-11.07). Through 49 days since the LMP, oral and buccal regimens performed similarly, but success with oral misoprostol decreased as pregnancy advanced. In pregnancies of 57-63 days since the LMP, success with oral misoprostol fell below 90%, whereas that with buccal remained high (oral 85.1% [97 of 114], buccal 94.8% [109 of 115], P=.015, RR 0.90, 95% CI 0.82-0.98). Furthermore, in this gestational age group, there were significantly more ongoing pregnancies among women who took misoprostol orally (7.9% [9 of 114]) compared with buccally (1.7% [2 of 115]; P=.029, RR 4.54, 95% CI 1.0-20.55). Adverse effect profiles were similar, although fever and chills were reported approximately 10% more often among women who took buccal misoprostol. Satisfaction and acceptability were high for both methods.
Conclusion: Buccal misoprostol 800 mcg after mifepristone 200 mg is a good option for medical abortion through 63 days since the LMP. Oral misoprostol 800 mcg is also a safe and effective alternative, although success rates diminish with increasing gestational age.
Clinical trial registration: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00386867
Level of evidence: I.