RESUMO
Noninvasive techniques of antenatal detection of the fetal development and well-being such as biophysical profile, non-stress and stress remain major challenges in modern obstetric practice. To obtain and analyze umbilical artery velocity waveform by pulsed-wave doppler ultrasound, a total of 160 determinations were carried out on 157 normal pregnant women between 16th to 41st week gestation. The ratio of peak systolic to end-diastolic flow velocity (S/D ratio), pulsatility index and resistance index were measured as indices of the resistance in feto-placental circulation. The results were as follows: As gestation advances, the mean values for peak systolic and end-diastolic velocities raised progressively. As gestation advances, the mean values for the S/D ratio declined progressively, exhibiting high diastolic flow velocity caused by low resistance. Pulsatility index, and resistance index were also declined progressively, as gestation advances. The analysis of umbilical artery blood flow velocity waveforms provides a new noninvasive technique to evaluate fetal development and well-being, and may be expected a reliable method for assessment of fetal life.