OBJECTIVE To determine the value of Doppler ultrasonographic examinations of the uterine artery in high-risk collectives and their importance as compared to examinations of the umbilical artery. METHODS In 142 patients with fetal growth retardation (birth weight <10th percentile) and/or pre-eclampsia/HELLP syndrome (as defined by ACOG criteria), the umbilical artery and the uterine arteries were examined bilaterally using a 3.5/5-MHz color Doppler system (Acuson 128). The patients were assigned to six groups according to the Doppler findings (uterine artery unilaterally/bilaterally normal/pathologic and umbilical artery normal/pathologic). For each group, the median of the birth weight and the gestational age at delivery was determined and the frequency of occurrence of complications was calculated. RESULTS In cases with pathologic results in all three vessels, the median gestational age at delivery and the median birth weight were significantly lower than in all other subgroups. Of the cases with pathologic findings in the umbilical artery only, 6% had pre-eclampsia/HELLP syndrome. However, this complication developed in 90% of the cases with pathologic findings in both uterine arteries. If only the umbilical artery was examined (and not the uterine arteries) the Doppler results were normal in 40 (28%) of the patients in our high-risk group, thus incorrectly simulating undisturbed placental hemodynamics. CONCLUSIONS Examination of both uterine arteries is an indispensable element of Doppler examination to assess placental performance and risk to the fetus.