Effectiveness of early medical abortion using low-dose mifepristone and buccal misoprostol in women with no defined intrauterine gestational sac.

BACKGROUND The study was conducted to assess the effectiveness of early medical abortion (EMA) in women with early pregnancy and no defined intrauterine gestational sac (IUGS) on ultrasound. STUDY DESIGN Retrospective, multicenter, observational study of oral mifepristone 200 mg and buccal misoprostol 800 mcg administered 24-48 h later for EMA (gestations ≤ 63 days). Odds ratios (ORs) [95% confidence intervals (CIs)] of EMA failure and continuing pregnancy for women with no defined IUGS vs. those with confirmed IUGS were calculated. RESULTS Women with no defined IUGS were more likely to experience EMA failure [9.0% (6/67) vs. 3.5% (465/13,345); OR (95% CI)=2.72 (1.17-6.33), p=.041] and continuing pregnancy [7.5% (5/67) vs. 0.6% (83/13,345); OR (95% CI)=12.72 (4.98-32.46), p<.001]. CONCLUSION EMA failure is more likely in women with early pregnancy and no defined IUGS than those with gestations ≤ 63 days and confirmed IUGS.