Splunder, I.P. van

velocity umbilical venou waveform pregnancy doppler ductus venosus fetus artery study ductu gestation umbilical venous pulsations venosu umbilical vein flow velocity waveforms vena cava change pulsatility index blood umbilical artery pressure level pulsation index chapter ultrasound time-averaged aorta recording wavefonn atrioventricular pulsatility diastolic wladimiroff blood flow heart obstet time-averaged velocity volume increase trimester circulation volume flow figure flow velocity wavefonns impedance difference vessel measurement transmitral relationship wladimiroff jw gradient small-for-gestational age fetus atrial contraction ratio stewart pa transvaginal right atrial growth retardation location systolic cm /s placental huisman parameter 20 weeks analysis contraction result rizzo reduction peak systolic velocity valve venous vessels transtricuspid growth time-averaged velocities