Comprehensive assessment of fetal wellbeing: which Doppler tests should be performed?
OBJECTIVE
Doppler applications in pregnancy are expanding exponentially. Flow velocity waveforms provide important information 12 weeks to term, from maternal vessels, placental circulation and fetal systemic vessels, with implications for both mother and fetus. As applications proliferate, awareness of the complexity of fetal and placental circulations, in normal pregnancy and in sequential responses to compromise, has also grown. The necessary data are now available to establish core values in Doppler evaluation for at-risk pregnancies.


RESULTS
Uterine arteries depict maternal vascular effects of the invading placenta, predicting the frequency and severity of pre-eclampsia and intrauterine growth restriction. New evidence suggests early treatment based on this principle, significantly reduces these impacts. Umbilical artery Doppler reflects downstream placental vascular resistance, strongly correlated with intrauterine growth restriction and the multisystem effects of placental deficiency. Abnormalities are progressive, with reduction, loss, and finally a reversal of diastolic flow. When umbilical arteries become abnormal, the differentiation of fetal status requires Doppler information from systemic vessels. Middle cerebral artery changes begin when the redistribution of cardiac output reflects rising placental resistance, demonstrating 'brain sparing' when cerebrovascular dilation occurs. In the compromised intrauterine growth retarded fetus, precordial veins illustrate fetal cardiac function, changing as the respiratory status declines. This Doppler information is combined with biophysical profile scoring to determine the need for and timing of intervention.


CONCLUSIONS
Doppler evaluation of at-risk pregnancies provides crucial prognostic and diagnostic detail about placentation and fetal adaptation. What has been research detail is now becoming the standard of care, in comprehensive fetal-maternal assessment.
Harman
Chris R
CR
Center for Advanced Fetal Care, Department of Obstetrics, Gynecology and Reproductive Science, University of Maryland School of Medicine, Baltimore, Maryland, USA. charman@umm.edu
Baschat
Ahmet A
AA
D001783:Blood Flow Velocity; D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging*; D005333:Fetus / Q000098:blood supply*; D005865:Gestational Age; D006801:Humans; D017078:Laser-Doppler Flowmetry; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000502:physiology; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging / Q000502:physiology; D014471:Umbilical Veins / Q000000981:diagnostic imaging / Q000502:physiology