Doppler Velocimetry of the Umbilical and Uteroplacental Circulation: A Critical Review

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Abstract
During the past 8 years, there have been more than 300 articles published describing Doppler studies in the field of obstetrics. This review will analyze the data dealing with the umbilical and uteroplacental circulation. This is being done with the goal of formulating an opinion of the role of Doppler in the practice of clinical obstetrics. We have concluded from prospective studies that there is no clear definition of abnormal umbilical flow velocity before 30 weeks, except for absent end‐diastolic velocity after the 20th week. Most of the prospective studies on the uteroplacental circulation have suffered from a lack of knowledge of the umbilical circulation, or only one uterine artery was studied. Most investigations until now have focused on demonstrating the pathophysiological correlations with Doppler studies. With the exception of a few dissenting voices, most have demonstrated strong correlations at probability levels of < 0.01. A few studies have emerged that have attempted to evaluate Doppler as a screening or surveillance tool. The results have not been encouraging. In populations with a low perinatal mortality, it will be difficult to prove that Doppler will reduce perinatal mortality. Studies of Doppler efficacy will have to be designed to show improved usage and efficacy of fetal surveillance. Since Doppler uniquely identifies the fetus at risk for hypoxia before term, it could replace our current risking system for the detection of fetal disease. This implies a reduction in the need for serial nonstress test, contraction stress test, and ultrasounds for amniotic fluid volume in those pregnancies with normal uterine and umbilical flow velocity.