TABLE B1.5 Uterine Activity During Early Pregnancy in Control and RU 486-Treated Patients (Montevideo units; mean ± SEM)

 

Control

36 Hours After 50 mg of RU 486

Mean uterine activity

6 ± 4

222 ± 93

Sulprostone, 0.05 mga

49 ± 24

711 ± 136

NOTE: SEM = Standard error on the mean.

a Administered 0.5 hour after start of recording.

SOURCE: Swahn and Bygdeman (1988).

250 µg injected intramuscularly) was the prostaglandin used most. In Great Britain, the trials with gemeprost (a PGE1 analogue, 0.5 mg administered vaginally) were satisfactory when given up to 63 days of amenorrhea; registration (approval) was acquired there in July 1991, and in Sweden in 1992 with the same protocol. The largest study (Ulmann et al., 1992) indicated 95 percent complete efficacy, with 1 percent of ongoing pregnancies, emphasizing the obligation to evacuate the uterus instrumentally in case of failure. There were no particular bleeding problems—only approximately 1/1000 patients received a transfusion. However, three myocardial infarctions, including one fatal case (a medical mistake occurred when sulprostone was injected into a woman at great risk), were recorded after more than 60,000 cases. Sulprostone for intramuscular administration has since been withdrawn from the market in France.

Coincidentally, the death of a patient (having received intramuscular Sulprostone) was reported at the same time as the first trial of RU 486 plus orally active misoprostol (a PGE1 derivative) was published (Aubeny and Baulieu, 1991). We had hoped to use a safer prostaglandin (misoprostol has a record of millions of users for the prevention and treatment of gastrointestinal ulcers in individuals often at greater cardiovascular risk than normal pregnant women). It was also obvious that an orally effective, already available, cheap, and easy to store prostaglandin had the potential to be an important improvement, since it could allow a more convenient and private method of abortion. Most results (Peyron et al., 1993) have been obtained by using 600 mg of RU 486 and 400 µg (two tablets) of misoprostol 48 hours later. Four hours after misoprostol, approximately 70 percent of women aborted; if expulsion did not occur, a third misoprostol tablet (200 µg) was proposed to the patients. Greater than 98 percent efficacy was achieved according to the current trials for women with =49 days amenorrhea pregnancies (Table B1.6). Besides safety, this regimen was well tolerated—uterine cramps were minimized. Details and discussion of the method are found elsewhere (Peyron et al., 1993).



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