A total of 568 perinatal deaths occurred along with 25,111 childbirths, with 92 infants exhibiting malformations detrimental to life. The latter figure accounted for 16.2 per cent of all perinatal deaths or for 0.37 per cent of all childbirths. --Sixty per cent of the above malformations would have been detectable, had prenatal diagnosis been undertaken for the discovery of genetic defects. Every third malformation occurred along with a neural tube defect of which 93 per cent would have been detectable. Hydramnion in the course of pregnancy has proved to be the most specific indicator to malformation, and in 26 per cent of all pregnancies examined it was found to be present in concomitance with prenatally detectable malformations. Other data recordable in the context of pregnancy, including case history, hyperemesis, imminent abortion, gestosis, maternal infections, and exogenous noxae, were found to be unspecific and, consequently, not reliable for prenatal diagnosis. General ultrasonographic B-scan examination of all pregnant women would most probably help to detect 30 per cent of all malformations observed in this study, while prenatal detection of another eleven per cent seemed to be possible with less certainty. Such high rate of prenatal detection would help to reduce perinatal mortality by 6.7 per cent. Alpha-foetoprotein in maternal serum should be determined from all pregnant women, with the view to recording neural tube defects. Such step would be conducive to the detection of one third of all malformations. Further reduction of perinatal mortality and even more morbidity is thought to depend strongly on an expansion of indications for prenatal diagnosis.