Circulating levels of placental protein 12 and chorionic gonadotrophin following RU 38486 and gemeprost for termination of first trimester pregnancy.

First trimester termination of pregnancy was successfully induced in ten patients with RU 38486 followed 2 days later by a prostaglandin (Gemeprost) pessary. Human chorionic gonadotrophin (HCG) values remained unaltered until after the abortion. The levels of placental protein 12 (PP12) showed an immediate and significant fall following RU 38486, then rose to values substantially higher than those at the initial visit after 2 days. These findings show that RU 38486 has a direct inhibitory effect on tissues producing PP12 and confirm the progesterone dependency of this protein.