Noninvasive Doppler and Ultrasound Parameters to Predict Fetal Anemia Due to Red Blood Cell Alloimmunization

Objective: To evaluate the screening efficiency of ultrasound and Doppler measurements in the prediction of fetal anemia in alloimmunized pregnancies. Materials and Method: In a prospective study, 24 nonhydropic fetuses with red blood cell alloimmunization were evaluated with ultrasound and Doppler imaging. Middle cerebral artery peak systolic velocity, intrahepatic umbilical venous maximum velocity, liver length, and spleen perimeter were measured. Results before first fetal blood sampling or delivery were analyzed. Results: Eighteen fetuses were anemic and required intrauterine transfusion, and 6 were not severely anemic at birth. Middle cerebral artery Doppler imaging was the best predictor of fetal anemia (94.4%), followed by intrahepatic umbilical venous maximum velocity (72.2%). Sensitivity was low for spleen perimeter (55.5%) and liver length (50%). The areas under the curve equal to 0.972, 0.861, 0.667 and 0.528 for middle cerebral artery peak systolic velocity, intrahepatic umbilical venous maximum velocity, liver length, and spleen perimeter respectively were determined for the prediction of fetal anemia. Conclusion: Middle cerebral artery peak systolic velocity is the best available noninvasive test in the prediction of fetal anemia.