Meta-analysis of 200 or 600 mg mifepristone in association with two prostaglandins for termination of early pregnancy
Contraception 80(1): 95-100
Publication date: 2009
There is unsettled controversy about the respective efficacy and safety of 200 and 600 mg mifepristone in combination with two prostaglandins for the termination of pregnancy up to 63 days' gestation.
We performed a meta-analysis of randomized controlled trials (RCTs) of direct comparisons between the two dose regimens. End points were complete abortion, continuing pregnancy and side effects.
Four RCTs (3482 patients) were found. Noninferiority of 200 mg mifepristone compared with 600 mg was proven for complete abortion [difference, 0.4%; 95% confidence interval (CI)=-1.4% to 2.3%]. Noninferiority was not proven for continuing pregnancy (difference, 0.4%; 95% CI=-0.3% to 1.0%). Two hundred milligrams may therefore result in 1% more continuing pregnancies than 600 mg when used with the approved prostaglandin regimens. Sensitivity analyses confirmed the findings. There was no difference in adverse events between both doses of mifepristone.
Although 200 or 600 mg of mifepristone with two prostaglandins probably results in similar rates of complete abortion, the substitution of 200 mg for 600 mg may lead to an increased continuing pregnancy rate.