The use of prostaglandins and antiprogestins for pregnancy termination

Abstract

Although vacuum aspiration could be regarded as a simple procedure, complications do occur and attempts have been made to develop non-surgical procedures for termination of pregnancy during the first 3-4 weeks following the first missed menstrual period. A variety of prostaglandin (PG) analogs have been developed which are equally effective as vacuum aspiration to induce abortion during early pregnancy. However, the widespread acceptance of PG treatment is limited by a relatively high incidence of gastrointestinal side effects and uterine pain. Treatment with presently available antiprogestins alone is not sufficiently effective to compete with vacuum aspiration. However, administration of these compounds induces uterine contractions and increases the sensitivity of the myometrium to prostaglandin. These effects allow the development of sequential treatment with RU 486 and a low dose of PG analogs administered intramuscularly or vaginally which is highly effective and is seemingly associated with a lower frequency of side effects than if PG analogs are used alone. It can be concluded that this medical abortion method has the capacity to compete with vacuum aspiration for termination of early pregnancy. Randomized studies comparing the two procedures are, however, needed to confirm this statement.