Transvaginal ultrasound in selective embryo reduction for multiple pregnancy.

Ovulation induction for the treatment of infertility is known to carry the risk of inducing multiple gestations, with attendant high perinatal morbidity and mortality. Selective reduction of the number of fetuses in a multiple gestation to reduce this risk, using transvaginal ultrasound, is a recent technological development. Six patients (three with quadruplets and three with triplets) underwent selective embryo reduction in the first trimester using real-time transvaginal ultrasound. Potassium chloride was used for intrathoracic injection. One of the procedures was complicated by chorioamnionitis 48 hours later, necessitating termination of pregnancy. Transvaginal sonographically directed selective reduction represents an important addition to the management of unplanned multiple pregnancy resulting from infertility treatment. The procedure is not without risks, and these must be weighed against potential benefits.