Cardiac output in a fetus with erythroblastosis fetalis: assessment using pulsed Doppler.

Pulsed Doppler studies of left and right ventricular outputs were obtained over time in a hydropic fetus with erythroblastosis fetalis. Despite severe anemia, cardiac outputs were within the normal range and remained normal after in utero percutaneous intravascular transfusions, which reversed the hydrops. The measurement of cardiac output in utero provides direct evidence that high-output failure due to anemia is not the mechanism for hydrops in erythroblastosis fetalis.