Receiver operating characteristic curves of fetal, umbilical and uteroplacental blood velocity waveforms as predictors of fetal outcome.

The maximum blood flow velocity waveforms (FVW) were recorded by a pulsed Doppler ultrasound from the fetal aorta, umbilical artery and arcuate artery in 142 pregnancies suspected of intrauterine growth retardation (IUGR) according to ultrasound fetometry. The FVW were analysed for pulsatility index (PI) and Blood Flow Class (BFC). The aim of the study was to find the optimal parameter and cut-off level for predicting the outcome of pregnancy. Receiver operating characteristic curves were used for the analysis. The umbilical artery PI and BFC shows the strongest relationship to IUGR. The optimal cut-off point was found at 2 SD above the mean PI of the normal population. The aortic PI had a relatively low predictive value for IUGR, but the absence of aortic end-diastolic velocities (BFC 2 and 3) was the best parameter for predicting fetal distress. The arcuate artery PI had low predictive capacity for fetal outcome. The data indicate that the absence of diastolic velocities in the fetal aorta and the umbilical artery PI, with the cut-off level of 2 SD above the mean for the normal population, are the best and comparable blood flow parameters, which can be used for monitoring fetuses suspected of IUGR.