Umbilical Artery Doppler Velocimetry During Oxytocin Challenge Test and Its Clinical Significance

Objective To study the value of Oxytocin challenge test (OCT) in high-risk pregnancy with abnormal umbilical artery resistance and the clinical significance of performing the umbilical velocimetry during OCT. Methods One hundred and seventy patients with abnormal umbilical artery resistance but maintained forward diastolic flow and 178 patients with normal umbilical blood flow received OCT, umbilical velocimetry was conducted during OCT. If the umbilical artery pulsatility index (PI) increased more than 0.5 during contraction and OCT was positive, cesarean section was performed in the same day, otherwise, vaginal delivery was tried. Results The rate of positive OCT was 45.3% and 10.1% respectively and the rate of positive OCT with umbilical artery PI increasing more than 0.5 was 37.4% and 6.7% respectively in abnormal umbilical artery flow resistance group and normal umbilical artery flow group ( P 0.001). For 19 cases with positive OCT but no increase in umbilical artery PI, 15 cases were successful vaginal delivery. In negative OCT group, 30 cases had the operative delivery for fetal distress (ODFD) during labor, among which the umbilical artery flow resistance of 24 cases increased during OCT ( P 0.001). For cases of poor perinatal outcome, 78.6%～81.8% were ODFD. Conclusions Umbilical artery doppler velocimetry during OCT is a good method to detect compromised fetus earlier in cases with abnormal umbilical artery blood flow; it is important in reducing the rate of the false positive and false negative OCT; it has clinical significance in improving the perinatal outcome.