During three and a half years we observed 83 single pregnancies all delivered by caesarean section. All of them had a mild (systolic blood pressure > 140, diastolic > 90 and proteinuria > 0.5 g/dl) or a severe preeclampsia (systolic blood pressure > 160, diastolic > 100 and proteinuria > 3.0 g/dl). We found significantly twice as many abnormal uteroplacental blood flow velocities in the severe preeclampsia group than in the mild one. These results draw us to the conclusion that possible pathological changing of the vessels is due to preeclampsia which does not need to correlate with a placental insufficiency and fetal growth retardation. An abnormal uteroplacental blood flow velocity connected with an abnormal umbilical blood flow velocity raises the fetal morbidity and the early childhood morbidity. Fetal outcome in mild compared to severe preeclampsia definitively shows a worse prognosis for those fetuses whose mother developed a prepartal severe preeclampsia. A distinctly increased rate of cerebral haemorrhages, abnormal neurological signs, acute respiratory distress syndromes and bronchopulmonary dysplasia was found. Finally we show an additional risk for fetal outcome in absent or reverse enddiastolic flow velocity (AREDFV) in the severe preeclampsia group. We observed in the AREDFV group with severe preeclampsia in comparison to a group of AREDFV without maternal preeclampsia more than twice as many cerebral haemorrhages, abnormal neurological signs and bronchopulmonary dysplasia.