[Doppler sonography of the umbilical artery, mode of delivery and perinatal morbidity in prolonged pregnancy].

130 women with postterm pregnancies (281-297 days of gestation) were examined with pulsed Doppler ultrasound of an umbilical artery. The result was not included in clinical decisions. In the group with abnormal flow a high rate of cesarean sections because of fetal distress (53%) was necessary, whereas only 3% were performed in the group with normal flow. In cases with reduced enddiastolic blood flow velocity the fetal outcome was significantly worse compared with cases with normal flow. The sensitivity of pulsed doppler ultrasound in predicting cesarean section for fetal distress was 71%, the specificity 91% (3 days before delivery). The oxytocin challenge test indicated this with a sensitivity of 58% and a specifity of 82%, whereas the nonstress test is not useful in predicting fetal risk in postterm pregnancy.