Based upon the pharmacokinetics of mifepristone, we postulated that repeating a dose after its half-life period may potentiate its abortifacient effect.
We administered mifepristone (200 mg) on days one and two, and misoprostol on day three (200 or 400 μg, vaginally, six-hourly, upto three doses in 12 h) in 100 women (intervention group). We compared their outcome with that of another 100 women who received the one-dose mifepristone regimen (mifepristone on day one and misoprostol on day three) during the months immediately preceding the study period (historical controls).
The mean age, parity and gestation (18 weeks) were similar in the two groups. On day three (before initiating misoprostol), cervix admitted one finger in significantly more women in the intervention group (36 versus 8% in historical controls; p = 0.001). All women aborted successfully in the two groups. The IAI of the intervention group was significantly shorter than the IAI of historical controls (10.45 vs 13.75 h; p = 0.013), and the misoprostol requirement was also significantly lower (mean 434 vs 500 μg among historical controls, p = 0.04).
Second-trimester medical abortion using two sequential doses of mifepristone followed by misoprostol reduced the IAI and misoprostol requirement without adding any extra days to the existing regimen. Further randomized studies can assess if the ‘two-dose’ mifepristone regimen is more efficient than the ‘one-dose’ regimen.
Mifepristone; Misoprostol; Second-trimester abortion.