The conventional timing of misoprostol administration after mifepristone
for medical abortion is 2 days, but more flexible intervals, which may make
the regimen more convenient, have not been studied.
To determine whether vaginal misoprostol administered 1, 2, or 3 days
after mifepristone influences safety or effectiveness for abortion at up to
56 days' gestation.
Prospective, randomized, open-label trial conducted from March 1998
to June 1999.
Sixteen US primary care and referral abortion facilities.
A total of 2295 healthy patients aged 18 years or older who were 56
or fewer days pregnant. Forty (1.7%) were lost to follow-up.
Patients received 200 mg of oral mifepristone and were randomly assigned
to self-administer 800 µg of vaginal misoprostol at home 1 (n = 745),
2 (n = 778), or 3 (n = 772) days later. Women returned to the clinic up to
8 days after mifepristone for ultrasonographic evaluation. A second dose of
misoprostol was administered if the abortion was not complete. Patients with
continuing pregnancy, excessive bleeding, or retained pregnancy tissue 5 weeks
later received an aspiration curettage.
Main Outcome Measures
Effectiveness of the procedure (ie, a complete medical abortion without
surgical intervention), adverse effects, acceptability of the procedure based
on patient questionnaires, reasons for surgical intervention, and adverse
outcomes, compared among the study groups.
Of the 2255 women completing follow-up, complete medical abortion rates
were 98% (95% confidence interval [CI], 97%-99%) among those using misoprostol
after 1 day, 98% (95% CI, 97%-99%) for those using misoprostol after 2 days,
and 96% (95% CI, 95%-97%) among those using misoprostol after 3 days. Fifty-five
subjects aborted before taking misoprostol, 9 had early surgery, and 103 did
not take misoprostol on their assigned day. No blood transfusions were required.
Cramping and nausea were the most common adverse effects reported, with similar
percentages of patients in all 3 groups reporting such effects. Thirteen unexpected
or serious adverse events occurred: 6 in those using misoprostol after 1 day;
4 in those using it after 2 days; and 3 in those using it after 3 days. Nearly
all women (>90%) found the procedure to be acceptable.
Our results suggest that vaginal misoprostol, 800 µg, can be used
from 1 to 3 days after mifepristone, 200 mg, for early medical abortion, and
need not be administered strictly 48 hours after mifepristone.