[Fetal umbilical artery velocity waveforms to predict the outcome in high risk pregnancy and its correlation with placental pathology].

Pulsed-wave Doppler ultrasound was used to measure the umbilical artery flow velocity S/D ratio in 101 high risk pregnancies. S/D ratio represented the ratio of maximum systolic velocity (S) to minimum diastolic velocity (D), The result of performing the receiver operating curve demonstrated that the cut off point of 2.8 had the best predictive value with sensitivity 0.706, specificity 0.976, accuracy 0.92 and false positive value 0.024. The abnormal pregnancy outcomes of S/D > 2.8 were obviously higher than of S/D < 2.8 (P < 0.01). In order to investigate the correlation of S/D ratio and placental pathology, 29 pregnant women were divided into 3 groups: (1) 10 normal pregnancies with S/D < 2.8; (2) 9 high risk pregnancies with S/D < 2.8; (3) 10 high risk pregnancies with S/D > 2.8. The result of placental pathological examination showed that the mean number of small muscular arteries of the tertiary stem villi per 100 microscope low power field (LPF) was less in the high risk pregnancy with S/D > 2.8 group (2.15 +/- 0.16 than in the other two groups (4.84 +/- 1.6, 4.17 +/- 1.4, respectively) (P < 0.01). Our study suggested that the umbilical artery Doppler was a useful screening tool for identifying the abnormal outcomes in high risk pregnancies and its main placental pathological finding was the obliteration of small muscular arteries in the tertiary stem villi.