Role of Doppler sonography in fetal/maternal medicine.
Doppler velocimetry of umbilical, fetal, and uteroplacental vessels provides important information on fetal and uterine hemodynamics and has therefore become one of the most dynamic areas of perinatal research. Examinations of umbilical artery velocity waveforms have gained recognition as a valuable clinical method of fetal surveillance in risk pregnancies. Pathological Doppler findings, especially the finding of absent or reverse end-diastolic (ARED) flow velocity, are associated with fetal hypoxia and adverse outcome of pregnancy. The first follow-up studies indicate that abnormal Doppler findings are associated with impaired postnatal neurological development. Velocimetry of the fetal middle cerebral artery provides important information on redistribution of fetal blood flow in hypoxia; its place in clinics remains to be established. Similarly, more studies are needed to evaluate the use of Doppler velocimetry in labor. Possibly, the Doppler method may facilitate the interpretation of equivocal cardiotocography (CTG) tracings. New evidence has been collected on the correlation between hemodynamic findings and the morphology of the placenta and the placental bed. One of the very important applications of Doppler velocimetry is the evaluation of pharmacological effects on fetal circulation of drugs used for treatment in pregnancy and labor.