Pulsed-wave and color Doppler ultrasound examination of the uterine and umbilical arteries was performed in patients with preeclampsia (Acuson, Sequoia, Mountain View, CA) using a 3.5 or a 5 MHz curvilinear probe. Transducers were directed toward the iliac fossa, the external iliac artery was imaged in a longitudinal section, and the uterine artery was mapped with color Doppler as it crossed the external iliac artery. Pulsed-wave Doppler was performed of both uterine arteries and when three similar consecutive waveforms were obtained, the resistance index (RI) of the right and left uterine arteries was measured and the mean RI of the two vessels was calculated. Uterine artery Doppler velocimetry30 (link) was defined as abnormal if either the mean RI was above the 95th percentile for gestational age31 (link)or in the presence of a bilateral early diastolic notch.32 (link) The Doppler signal of the umbilical artery was obtained from a free floating loop of the umbilical cord during the absence of fetal breathing and body movement. When three similar consecutive waveforms were obtained, the pulsatility index (PI) was measured. Umbilical artery Doppler velocimetry was defined as abnormal if either the PI was above the 95th percentile for gestational age using the reference range proposed by Arduini and Rizzo33 (link)or in the presence of abnormal waveforms (absent or reversed end diastolic velocities) as described by Trudinger et al.34 (link) The patients were classified into the following 4 groups: 1) Normal Doppler velocimetry in the uterine and the umbilical arteries; 2) Doppler abnormalities in the uterine artery alone; 3) Doppler abnormalities in the umbilical artery alone; and 4) Doppler abnormalities in both vessels.