The significance of absent end-diastolic velocity in umbilical artery velocity waveforms.

Doppler umbilical artery velocimetry has been used to study high-risk pregnancies. The most extreme waveform abnormality is the absence of end-diastolic velocity. To examine the significance of this finding, events outcome was evaluated in 161 women studied between 31 and 36 weeks. Ten had absence of end-diastolic velocity. When compared with fetuses with normal and less severely abnormal waveforms, there was a higher incidence of intrauterine growth retardation, pregnancy-induced hypertension, cesarean section for fetal distress, neonatal intensive care unit admission, and low Apgar scores. Average birth weight and gestational age at delivery were lower. Five other fetuses with absence of end-diastolic velocity were identified that were delivered between 27 and 30 weeks, making a total of 15 patients with absence of end-diastolic velocity. Of 12 patients monitored, 11 had an abnormal fetal heart rate pattern. Four fetuses had lethal anomalies. There were eight perinatal deaths. Acute or chronic hypoxia was evident in all fetuses with absence of end-diastolic velocity. Absent end-diastolic velocity represents a unique and severe fetal condition that cannot be identified by present surveillance methods and requires a Doppler study for diagnosis.