We analysed 78 fetuses with absent or reverse endiastolic flow velocities (AREDFV) of the umbilical arteries with respect to fetal acidosis, resistance index of the middle cerebral artery (MCA) and abnormal neurological evaluations. A control group was matched for gestational age and normal umbilical artery flow velocity waveforms. Fetuses with AREDFV showed an increased incidence of fetal acidosis. The number of fetuses with abnormal neurological signs was significantly increased compared to the control group. Most of these fetuses (86%) showed abnormal blood flow velocity waveforms of the middle cerebral arteries called "brain-sparing effect". The combination of premature delivery in the 30th week of gestation, severe idiopathic respiratory distress syndrome, and a resistance index under the 10th percentile in the middle cerebral arteries seems to be a risk factor of the early neurological morbidity in fetus with AREDFV.