UMBILICAL ARTERY BLOOD-FLOW CHARACTERISTICS IN NORMAL PREGNANCIES

585 pregnant women were investigated with both conventional sonographi c examination and color Doppler examination. The cases with intrauteri ne growth retardation, preeclampsia, twin pregnancies, congenital malf ormations and diabetes were excluded. The remaining 550 cases (between ages 16 and 40) were investigated in the first trimester and gestatio nal ages were compatible with the last menstrual date. In order to eva luate fetal development, biparietal diameter, femur length, abdominal circumference, and estimated fetal weight were calculated by conventio nal ultrasonographic method. The application of Doppler ultrasound to the study of fetal umbilical arterial blood flow velocity is a relativ ely new technique. The failure to obtain useful Doppler signals was ab out 18-22% with pulse-wave Doppler system. Recently, color Doppler tec hnology solved this problem. We used an ALOKA 680-SSD ultrasonography device and color Doppler ultrasonography technique and recorded umbili cal arterial Doppler signals from every case and calculated classical Doppler indices - systolic/diastolic (S/D) ratio, pulsatility index (P I), Pourcelot index or resistive index (RI). Statistical comparisons w ere made by SPSS program. Correlation coefficient and R(2) values betw een gestational age and other indices were calculated. The aforementio ned values were r: -0.79; R(2): 0.63, r: -0.71; R(2): 0.50, r: -0.64; R(2): 0.41, for S/D, PI, RI, respectively.