Prediction of fetal distress and poor outcome in prolonged pregnancy using Doppler ultrasound and fetal heart rate monitoring combined with stress tests (II).

Postterm pregnancies of more than 290 completed gestational days (n = 110) were simultaneously supervised after admission by pulsed Doppler ultrasound of the common carotid and the umbilical arteries, nonstress and contraction stress tests (NST/CST) and vibroacoustic stimulation tests (VAST). The results of these tests were blinded for the clinicians. Further decision making was based mainly on fetal heart rate (FHR) monitoring. The prognostic value of tests performed < 3 days before birth predicting fetal distress, low Apgar and pH values in the umbilical artery were compared by receiver operator characteristics. Results of the NSTs and fetal Doppler measurements of the ratio of resistance indices of common carotid/umbilical artery were more predictive of later fetal distress than both, VAST and CST (p < 0.01, p > 0.05, respectively). There were no significant differences in the prediction of low Apgar values. NST was the only significant test for predicting a low pH in the umbilical artery immediately after birth compared to the other examinations (p < 0.05). The results suggest that even in prolonged pregnancies VAST and CST might be released from routine supervision.