Significance of an absent or reversed end-diastolic flow velocity in Doppler umbilical artery waveforms.

Doppler velocity waveform analysis has been introduced as part of antenatal fetal biophysical assessment. Abnormal waveforms are associated with maternal and fetal complications. The most severe waveform patterns observed, absent end-diastolic velocity (AEDV) and reversed end-diastolic velocity (REDV), are of ominous significance in many cases but the incidence of these waveforms is low and the outcome is varied. The purpose of this study is to assess perinatal outcome in patients showing absent end-diastolic velocity (AEDV) and reversed end-diastolic velocity (REDV) in umbilical artery flow velocity waveforms. We reviewed our experience of patients showing AEDV and REDV in the umbilical artery flow velocity waveforms over nineteen months. Fifteen patients, all in high risk pregnancies, were identified during this period; 9 with AEDV and 6 with REDV. The results were not used in the clinical management. Twelve babies died (3 fetal deaths, 4 stillbirths and 5 neonatal deaths); giving the perinatal mortality is this group as 80 per cent. The interval between the abnormal waveform recording and fetal death or delivery was between 2 hours and 4 weeks. In three fetuses with abnormal diastolic flow, analysis of umbilical vein blood gases revealed severe acidosis and hypoxia. There was also significant perinatal morbidity as judged by low Apgar scores, days in neonatal intensive care, growth retardation and lethal anomalies. These findings suggest that once the diastolic component of umbilical artery flow velocity waveforms become absent or reversed, the fetus is in a state of hypoxia and acidosis and perinatal outcome is catastrophic.(ABSTRACT TRUNCATED AT 250 WORDS)