THE EFFECT OF THE ANTI-PROGESTIN MIFEPRISTONE (RU 486) ON PLASMA PROSTAGLANDIN METABOLITE LEVELS IN EARLY PREGNANCY AND ITS INFLUENCE ON PREGNANCY TERMINATION

The effect of a single dose of RU 486 (600mg) on prostaglandin metabolite levels has been studied over a 48 h period in 20 women undergoing medical termination of early pregnancy. The results were compared with controls of similar gestation who were treated surgically. The mean (SD) P GEM levels at 0 and 48 h in the RU 486 group were 13.7 (2.7) and 13.2 (2.2) pglml respectively, which was not significantly different from the values of 11.7 (1.1) and 11.3 (0.4) pglml measured in the control patients. Similarly the mean (SD) PGFM values of 22.3 (14.7) and 17.0 (7.2) pglml at 0 and 48 h were not significantly different from the corresponding control values of 21.9 (13.8) and 23.8 (7.2) pglml. In 10 of the study patients, there were no significant changes in PGEM and PGFM concentrations prior to and at 4, 24 and 48 h after RU 486 administration. Although all pregnancies were successfully terminated with the combination of RU 486 and subsequently a vaginal pessary containing PGE(1), no stimulation of prostaglandin production could be demonstrated.