The clinical implications of Doppler ultrasound analysis of the uterine and umbilical arteries.

Serial Doppler velocimetry of the umbilical and uterine arteries has revealed a relatively clear separation between normal and abnormal waveforms. Abnormal umbilical artery waveforms are defined by a systolic/diastolic ratio greater than or equal to 3 in the last 10 weeks of pregnancy. When abnormal waveforms persist, fetal growth retardation and adverse perinatal outcome are likely. Abnormal uterine artery waveforms are also recognized by a systolic/diastolic ratio averaged from both vessels of more than 2.6 after 26 weeks. In addition, the abnormal vessel will usually contain a persistent diastolic notching. Abnormal uterine vessels strongly correlate with the presence or subsequent development of preeclampsia and fetal growth retardation. Doppler velocity flow provides valuable insights into the pathophysiology of various disease states. It provides a basis for new clinical and basic research into disease mechanisms and methods for improving perinatal and maternal morbidity.