Predictive values of umbilical artery waveforms and repeat cardiotocography in pregnancies complicated by nonreactive cardiotocography

Fifty patients with a nonreactive nonstress cardiotocograph were studied. All had measurement of the A B ratio of the umbilical artery Doppler waveform and 39 also had a repeat nonstress test. The positive and negative predictive values of the repeat nonstress test were 61% and 94%, respectively, and those of the A B ratio were 67% and 83%. A repeat nonreactive nonstressed cardiotocograph appeared to be a test of high sensitivity (92%) and the A B ratio a test of high specificity (83%). It is suggested that the combination of the two tests may prove a powerful predictor of adverse perinatal outcome.