Objective To investigate the relationship between absent end-diastolic velocity of fetal umbilical artery (AEDV) and perinatal outcome. Methods The color Doppler ultrasound result of maximum flow velocity waveforms at the cardiac level (aorta, pulmonary artery) and the peripheral level (fetal umbilical artery, middle cerebral artery) in 27 cases with Umbilical artery AEDV were analyzed. Fetal heart rate monitoring was performed and perinatal outcome was followed up. Results All of the 27 cases presented with remarkable pulmonary artery contraction. The result of velocity time integral (VTI)?fetal heart rate (FHR) and right cardiac output declined significantly. Among 22 cases with continuous monitoring, 10 cases showed reduced PI of middle cerebral artery (MCA) without changes of left cardiac output; 12 cases had biphasic changes of the MCA PI which consisted of decrease followed by increase and showed significant reduction of VTI?FHR of aorta and left car-(diac) output. The interval between the first detection of AEDV and the presentation of abnormal FHR patterns was 2 to 7 days. Conclusions Umbilical artery AEDV usually precedes the presentation of abnormal FHR under fetal hypoxia. Delivery before decompensation may improve the perinatal morbidity and mortality.