Comparison of two dose regimens of misoprostol for second-trimester pregnancy termination

The study was conducted to compare the efficacy of two different dose regimens of misoprostol administered vaginally in combination with mifepristone for second trimester termination of viable and non-viable pregnancies.

Double-blind randomized controlled trial conducted at the University hospital in the Netherlands. One hundred seventy-six women between 14 and 24 weeks gestation with an intrauterine fetal death (n=31), congenital or genetic abnormalities of the fetus (n=116) or requesting a termination of pregnancy for psychosocial reasons (n=29) were studied. Randomization was into one of two groups. Both groups ingested mifepristone 200 mg. Depending on the randomization group, this was followed by either 200 or 400 mcg misoprostol given vaginally beginning 36-48 h later at 4-h intervals (with a maximum of 10 administrations in 48 h) until the fetus was delivered. Randomization, administration of the medication and assessment of the outcome was performed independently from the investigators. Main outcome measures were expulsion rate and the number of incomplete abortions warranting surgical evacuation of retained products of conception. Secondary outcome measures consisted of the time between the first administration of misoprostol to the delivery of the fetus, side-effects, blood loss, live births and changes in hemoglobin level.

In the 200-mcg misoprostol group, 66% (57/86) had a complete expulsion of fetus and placenta compared to 73% (66/90) in the 400-mcg group (p=NS). The time between the first administration of misoprostol and delivery of the fetus was significantly longer in the misoprostol 200-mcg group: mean 11.6 h (range: 9.7-13.5 h) versus 9.3 h (range: 8.1-10.5 h) in the 400-mcg group (p=.042). No significant differences between the groups were found for frequency of side-effects like nausea, retching, vomiting, fever, headaches and diarrhea. Blood loss was similar in both groups with a mean of 337 mL in the 200 mcg misoprostol and 296 mL in the 400-mcg misoprostol group (p=NS). Of the women with a viable pregnancy at the beginning of the trial, 18.6% (13/70) in the 200 mcg misoprostol group delivered a live fetus compared to 22.8% (17/75) in the 400 mcg misoprostol group (p=NS).

Both regimens used in this trial proved to be equally effective for termination of both viable and non-viable pregnancies during the second trimester. The time between the first administration of misoprostol and delivery of the fetus was significantly longer in the 200-mcg group than in the 400-mcg group. This outcome may be used as the rationale for choosing a 400 mcg misoprostol regimen for termination of pregnancy during the second trimester.