[Doppler measurements of blood flow velocity and waveforms in fetal venous circulation].

Ultrasonic velocimetry of the fetal circulation became a very useful method in assessment of fetal well-being, especially in high risk pregnancies. There are many papers concerning on distribution and regulation of blood flow in umbilical artery, middle cerebral artery, and much less dealing with flow velocity waveforms in inferior vena cava and ductus venosus and their clinical significance. Fetal compromise is associated with significant alterations in the fetal arterial and venous circulation. Changes in venous Doppler waveforms develop due to increased afterload and perhaps myocardial failure in deterioration after arterial redistribution is established. Doppler investigation of the fetal venous circulation may play an important role in monitoring the redistribution and may help to determine the optimal time for delivery.