Examination of the fetal cardiovascular system.

Doppler evaluation of the placenta and fetal cardiovascular system is one of the primary surveillance tools in prenatal medicine. By assessing uterine and umbilical arteries, placental development can be documented. This is useful for the prediction of hypertensive maternal disorders and placental dysfunction and fetal growth failure. The umbilical artery flow velocity waveform provides an estimate of villous vascular occlusion in the fetal compartment of the placenta. Middle cerebral artery Doppler is important in studying fetal responses to abnormal oxygenation and fetal anemia. Precordial venous Doppler gives insight into the cardiac effects of many conditions such as fetal growth restriction, twin-twin transfusion syndrome and fetal arrhythmia. Further quantification of these effects requires cardiac Doppler to quantify diastolic and systolic function as well as global myocardial performance. This article reviews important characteristics of arterial and venous Doppler waveform analysis, individual vascular beds and their clinical application in fetal evaluation.