Relationship Between the Fetal Heart Rate Pattern and Perinatal Mortality in Fetuses with Absent End-Diastolic Velocities of the Umbilical Artery: A Case-Controlled Study

ABSTRACT

Fetal decompensation is usually diagnosed by the onset of late decelerations and decreased fetal heart rate (FHR) variability and is associated with fetal hypoxemia and acidemia and has a high perinatal mortality. Objective analysis of the FHR pattern can be performed using the Fischer score and a score of less than 6 correlates with fetal decompensation. Fetuses with absent end-diastolic velocities (AEDV) of the umbilical artery have severe placental disease and coupled with this a high perinatal mortality and morbidity. Importantly, AEDV is usually observed before the occurrence of fetal decompensation. In fetuses with AEDV, delivery before decompensation may improve the perinatal mortality and morbidity. To test this hypothesis, the perinatal outcome of fetuses with AEDV delivered before decompensation (Fischer score of 6 or more), were compared with similar fetuses delivered after decompensation (Fischer score of less than 6). All FHR pattern records of fetuses who had AEDV with a birthweight greater than 750 g and a gestational age of 28 weeks or more were evaluated using Fischer's score by a single observer unaware of the perinatal outcome. Fifty-seven fetuses qualified for the study and 17 of these babies subsequently died. The babies who died had significantly lower mean Fischer scores during the preceding 6 hours before delivery (5.9 ± 1.8 SD) than the survivors (7.7 1.9; p <0.05), but also had lower birthweights and gestational ages. To obviate this effect, babies with a Fischer score of less than 6 at 6 hours before delivery (group 1) were matched to within 3 days gestational age and 10% birthweight with those with a Fischer score of 6 or more at 6 hours before delivery (group 2). Nineteen pairs were obtained. There were no differences in perinatal mortality and morbidity between the groups, although the surviving babies in group 1 spent significantly less time in the hospital (p <0.02). Therefore, waiting until a decompensation, as is evident from a low Fisher score, develops does not adversely affect the prognosis of the fetus.

Keywords

Absent end-diastolic velocity - fetal heart rate - decelerations - decompensation