A comparison of fetal heart rate monitoring and umbilical artery waveforms in the recognition of fetal compromise

Summary. Antenatal fetal heart rate monitoring was compared with the study of umbilical artery flow velocity waveforms for the recognition of fetal compromise in 170 patients considered at high fetal risk. In 53 patients the infant had a 5-min Apgar score of <7 and/or a birthweight < the 10th centile of weight for gestation. Fetal heart rate traces were classified as reactive or non-reactive and also assessed with a modified Fischer score. The systolic/diastolic A/B ratio was measured in the umbilical artery waveform. Fetal compromise was more efficiently recognized by study of the umbilical artery waveforms. The sensitivity of assessment by umbilical artery waveforms was 60% compared with 17% and 36% respectively, for the two methods of scoring fetal heart rate traces. This was not associated with an increase in false-positive results as the predictive value of both positive (64% compared with 69 and 58%) and negative (83% compared with 72 and 75%) results was similar when umbilical artery waveform analysis was compared with the two methods of scoring fetal heart rate traces. Specificity was also similar (85% compared with 97 and 88%).