The clinical significance of an absent end-diastolic velocity in the umbilical artery detected before the 34th week of pregnancy

Background. The aim of this study was to evaluate the clinical significance of absent or reversed (ARED) flow detected in the late second or early third trimester in the umbilical artery in high-risk pregnancies. Method's. Eighty-three women with hypertensive disorders of pregnancy, gestational diabetes or a suspected disorder of the fetus (e.g, small-for-gestational age) were included in this retrospective study A constant finding of ARED flow in the umbilical artery was registered with the pulsed Doppler method between the 23+0 and 33+6 gestational weeks. Perinatal mortality (PNM) rates, Apgar scores and arterial umbilical pH values, birth weights, the frequency of SGA, gestational ages at birth, NICU (=neonatal intensive care unit) days anomalic fetuses and the mode of delivery were registered. Mann-Whitney U-test and chi- squared test were used for statistical analysis. Results. The PNM in the entire group under study was 19.3% (16 infants/fetuses), The rate of structurally or chromosomally abnormal fetuses was 15.7% (13 infants/fetuses), When anomalic fetuses were excluded the PNM was 18.6%. No non-anomalic fetuses/newborns were lost in cases in which ARED was detected after the 30th week. No statistically significant difference was observed in PNM and SGA frequencies when comparing AEDV (absent end-diastolic velocity) fetuses with those who had REDV (reversed end-diastolic velocity). When anomalic fetuses were excluded the PNM rate in the AEDV group was 8.9% compared with the PNM rate of 35.7% in the REDV group; (p=0.03). Conclusions. An early ARED finding (before the 34th week) in the umbilical artery signifies a marked warning signal of fetal distress. In these cases the rates of perinatal morbidity and mortality are very high, which is a reflection of the severity of the condition. The majority of fetuses can, however, be saved.