Prediction of Fetal Acidosis by Blood Flow Velocity Waveform of the Fetal Descending Thoracic Aorta

Abstract

Fetal descending thoracic aorta blood flow velocity waveforms were measured in 63 pregnancies. They were either delivered by elective CIS before labor (56 patients) or suffered an antefartum fetal death (7 patients). There was a significant correlation between the aorta waveforms and the cord arterial pH. A cord arterial pH less than 7.20 or an intrauterine fetal death were used as our criteria for fetal acidosis. Using the above criteria, the specificities and negative predictive values of these testings in predicting fetal acidosis were over 80%. When fetal compromise was defined as either fetal acidosis or fetal growth retardation, the positive predictive values of these studies in forecasting fetal compromise heightened (range 81% to 92%) compared to those in predicting fetal acidosis (range 56% to 75%), although other predictive values remained similar. In conclusion, Doppler measurement of fetal descending thoracic aorta flow velocity waveform may be a valuable adjunctive noninvasive method of fetal surveillance.