Monitoring of intravascular fetal transfusions with Doppler velocimetry.

Intravascular fetal transfusions are occasionally complicated by extravascular deposition of transfused blood or by fetal bradycardia on penetration of the needle into the umbilical cord. It is desirable therefore to continuously monitor the intravascular location of the needle and the fetal heart rate. This can be achieved by Doppler velocimetry of the umbilical vein and artery during the procedure. The technique is easily performed, does not require moving of the ultrasonography transducer, and appears to be time efficient.