Uterine artery Doppler velocimetry in pregnant women with hypertension

The clinical significance of Doppler umbilical artery velocimetry in the small for gestational age fetus

Fifty-four women who were delivered of small for gestational age infants were studied antenatally by serially continuous-wave Doppler velocimetry. Outcomes were compared in the normal and abnormal systolic/diastolic ratio groups. Seventy-eight percent had an abnormal systolic/diastolic ratio. The group with an elevated systolic/diastolic ratio had a significantly higher incidence of abnormal fetal heart rate, pregnancy-induced hypertension, oligohydramnios, cesarean section for fetal distress, and admission into the neonatal intensive care unit. One third of the newborns required intermittent positive pressure ventilation. Average birth weight and gestational age at delivery were significantly lower and there were six perinatal deaths in the group with an elevated systolic/diastolic ratio and none in the group with a normal systolic/diastolic ratio. These data suggest that the small for gestational age fetus with normal umbilical artery velocimetry is at significantly lower risk than are those with abnormal ratios. This implies that management of the small for gestational age fetus may now be aided by a functional classification based on the umbilical artery velocity waveform.

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.

Development of uterine artery compliance in pregnancy as detected by Doppler ultrasound

Uterine artery velocimetry was performed by means of a continuous-wave Doppler ultrasound. Serial studies were done on 12 nonpregnant and 79 normal pregnant women. Measurements were made on both uterine arteries and averaged. From the proliferative phase of the menstrual cycle through 40 weeks of pregnancy, four developmental phases are described. These changes are based on the calculation of the systolic-diastolic ratio and the disappearance of the early diastolic notch in the velocity wave. The ratio after 26 weeks averaged 2 +/- 0.3. These data provide a foundation for the study of pregnancies in which these normal evolutionary changes do not occur.