Absence of End-Diastolic Flow Velocity in the Umbilical Artery: A Review

The objective of this review was to find the clinical relevance of the absence of end-diastolic flow velocity in the umbilical artery. Search was conducted through MEDLINE using unabridged MEDLINE Knowledge Finder (Aries System Corp., North Andover, MA). All the manuscripts published in English language within last 10 years (1983-1992) were included in the review process. There has been no report of umbilical artery absent-end diastolic velocity before 1983. It was extremely difficult to draw a conclusion because a majority of the available reports in the literature are either case reports or retrospective analyses. However, for the practical purposes it can be concluded that after viability these pregnancies should be followed by intense (daily) fetal well-being surveillance with conventional antenatal tests. Those who improve their end-diastolic velocity should be allowed to continue the pregnancy as long as antenatal testing is promising. Persistence of absent end-diastolic velocity may be an indication for delivery at a gestational age when there is reasonable chance of survival. Cytogenetic evaluation and anatomical survey of these fetuses by ultrasound is recommended. Long-term follow up of surviving infants needs to be studied. It is impossible for a single institution to accumulate enough cases for adequate outcome evaluation. A randomized prospective trial to assess the management of pregnancies with absent end-diastolic velocity in the umbilical artery would be difficult. Some might even consider such a study unethical. Until such a study is performed, an international registry would be helpful for collecting data about the perinatal outcomes and management of such patients.