[The significance of prenatal diagnosis of twins (author's transl)].

By means of ultrasound and fetal electrocardiography the diagnosis of twin pregnancies can be made prenatally without any reservation; the diagnosis is even possible in the first half of pregnancy. Comparative analysis of two approximately equal collectives of in all 602 twin pregnancies--1,45% of all births in the years 1955-1975 at the University Clinic for Gynecology and Obstetrics of the University of Cologne--revealed a better prognosis concerning the course of pregnancy and the new-born by prenatal diagnosis. The earliest possible diagnosis of twins, resulting in more intense clinical observation--and occasional clinical treatment--facilitated a significantly longer duration of pregnancy, leading to a higher percentage of mature twins. Whereas the total number of obstetric operations was reduced because of prenatal diagnosis, selection of highrisk cases led to a distinct increase in Caesarian sections. The prolongation of pregnancy, the higher birth weights and better maturity attained, were accompanied by decrease in perinatal mortality and in improvement in the Apgar-index of the newborn in that collective, in which prenatal diagnosis was achieved.