The abortifacient effect of misoprostol in the second trimester. A randomized comparison with gemeprost in patients pre-treated with mifepristone (RU486)

Hum Reprod. 1993 Oct;8(10):1744-6. doi: 10.1093/oxfordjournals.humrep.a137927.


The objective of this work was to study the abortifacient effects of misoprostol, an orally active prostaglandin E1 (PGE1) analogue, in the second trimester. A randomized study of two prostaglandin regimens in women pre-treated with the antiprogesterone mifepristone was carried out in the gynaecological wards of Aberdeen Royal Hospitals, NHS Trust, and included 60 women at 13-20 weeks' gestation, in whom termination of pregnancy had been agreed. Following pre-treatment with mifepristone 600 mg women were randomly allocated to one of two prostaglandin regimens which started 36-48 h later. The first misoprostol 400 micrograms orally (up to three doses) followed by gemeprost vaginal pessary 1 mg up to two doses. The second was gemeprost vaginal pessary 1 mg up to five doses. The main outcome measures were success rate induction-to-abortion interval and side-effects. There were no significant differences between the two groups in any of the main outcome measures. We conclude that misoprostol is a stable, cheap PGE1 analogue with demonstrable efficacy and acceptable side-effects in the management of second trimester abortion. Further work is needed to establish the optimum dose and regimen.

PIP: A total of 60 women having termination of pregnancy between 13 and 20 weeks were recruited to the study. Mifepristone 600 mg was given to all 60 patients in the clinic and 36-48 hours later they received the prostaglandin component of the treatment. Group 1 included 30 patients who were given misoprostol 400 mcg 3 hourly to a maximum of 3 doses. If abortion did not occur, 2 further doses of vaginal gemeprost 1 mg were administered 3 h apart. If abortion still did not occur, the treatment regimen was considered a failure and extra-amniotic prostaglandin E2 was administered. Group 2 patients were given gemeprost vaginal pessaries 1 mg, 3 hourly until abortion occurred, up to a maximum of 5 doses. If abortion did not occur, the treatment was considered a failure and extra-amniotic prostaglandin was initiated. Patients were kept for a minimum of 12 hours following the procedure. The patients were reviewed 14 days later. 27 (90%) of patients in group 1 and 28 (93%) in group 2 aborted successfully. Those aborting successfully in group 2 recorded a slightly higher median induction-to-abortion time than those in group 1. The median number of prostaglandin doses in both arms of the study was 3. In group 1, 23 patients (77%) aborted subsequent to receiving misoprostol only. 2 patients in group 1 aborted at 33 hours and 60 hours respectively. 14 (47%) patients in group 1 compared to 17 (57%) in group 2 required narcotic analgesia. Vomiting was 11 (37%) and 13 (43%), respectively, while diarrhea occurred in 6 (20%) patients and 2 (7%) patients, respectively. There were 5 cases of retained placenta, 2 from group 1 and 3 from group 2. 1 patient from each group bled heavily during the abortion. 2 patients from each group required exploratory dilatation and curettage because of heavy vaginal bleeding in the 2 weeks following the treatment. Follow-up was carried out for 36 patients (60%) at 2 weeks. The median duration of bleeding days for the 36 patients was 13 days. No patient experienced bleeding following mifepristone and prior to prostaglandin.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Abortifacient Agents, Nonsteroidal / pharmacology*
  • Administration, Intravaginal
  • Administration, Oral
  • Adolescent
  • Adult
  • Alprostadil / administration & dosage
  • Alprostadil / analogs & derivatives*
  • Alprostadil / pharmacology
  • Drug Administration Schedule
  • Female
  • Follow-Up Studies
  • Humans
  • Mifepristone / administration & dosage
  • Mifepristone / pharmacology*
  • Misoprostol / pharmacology*
  • Pessaries
  • Pregnancy
  • Pregnancy Trimester, Second


  • Abortifacient Agents, Nonsteroidal
  • Misoprostol
  • Mifepristone
  • gemeprost
  • Alprostadil