The clinical significance of absent or reverse end-diastolic flow in the fetal aorta and umbilical artery.

The clinical utility of Doppler blood flow investigations of the fetal and fetoplacental vessels is still under debate as far as timing of the delivery is concerned. However, in cases of absent or reverse end-diastolic flow, fetal compromise is usually very severe. As a consequence, we have investigated the possibility of using this information as a guide to obstetrical management. Altogether, 32 fetuses with absent or reverse end-diastolic flow in the fetal descending aorta and/or umbilical artery were studied. Reverse flow was observed in 11 cases and absence of end-diastolic flow in 21 cases. The two groups are considered separately. No significant difference was found in the mean gestational age at delivery. However, a highly significant difference was found in the mean birth weight and perinatal mortality rate. All the cases of perinatal mortality were encountered in the group presenting with reverse flow (mortality rate, 63.6%). All the live fetuses were delivered by Cesarean section and no neonatal mortality was observed in this group. Two cases of handicap were observed, one in each group. In our experience, reverse flow indicates the necessity for immediate delivery if no other clinical contraindications are present. Absence of end-diastolic flow can be observed for longer periods without adverse outcome. Absence of end-diastolic flow always precedes the appearance of fetal distress. Therefore, we believe that, after exclusion of conditions such as fetal abnormalities or extreme prematurity, a planned delivery should be considered.