Blood Flow Velocity Waveforms in the Ductus Venosus of Normal Fetuses

A total 60 normal pregnant women at 23-36 weeks gestation entered into this study.The ductus venosus(DV)was identified in two-dimensional imaging,color flow mapping and pulsed Doppler velocimetry.DV was a narrow trumpet-like vessel connected the umbilical sinus and the IVC.The narrowest portion never exceeded 2mm.The pulsatility of the DV blood flow had a characteristic pattern, reflecting ventricular systole,ventricular diastole and atrial systole.In contrast to the IVC,reversed flow was never seen during the atrial systole.The mean(SD)value of the DV for the peak velocity during ventricular systole was 55.1±12.92cm/s,for the peak velocity during ventricular diastole was 47.45±13.87cm/s,for the lowest velocity during atrium systole was 29.14±10.49cm/s,for the average velocity was 46. 04±12.36cm/s.The ductus venosus index computed[(ventricular systole-atrial systole)/ventricular systole] was 0.48±0.12.The DV flow was 27.53 ± 1 2.17ml/min.The flow ratio of DV and um5mcal vein was 0.32±0.16.The results show that the DV can be identified using pulsed Doppler technique.The high velocity supports the theory that the DV delivers well oxygenated blood for the preferential blood stream to foramen ovale and left heart.Probably 1/3 of the umbilical blood is shunted through the DV in normal human fetus.