Objective: To evaluate the utilisation measurements of peak systolic velocities in the middle cerebral artery (MCA-PSV) to predict fetal anemia in pregnancies complicated by alloimmune antibodies known to cause immunological hydrops. Design: A prospective study. Setting: Department of Obstetrics and Gynecology, University Hospital, Olomouc. Methods: In 38 pregnancies at risk for fetal anemia due to maternal red-cell alloimmunization MCA-PSV had been assessed and fetal blood sampling for measurement of hemoglobin concentration was obtained subsequently, either by cordocentesis or at delivery. Results: 66 examinations were performed at 19–37 week’s gestation. An MCA-PSV >1.5 MoM detected 100 % of severely anemic fetuses with a hemoglobin concentration <0.65 MoM that required invasive intervention. In 18 cases a cordocentesis was performed and intrauterine blood transfusion was given alternatively. Remaining fetuses did not require invasive intrauterine intervention and no or mild hemolytic anemia and hyperbilirubinemia were diagnosed after delivery. No false positive case was identified (enregistered). The median maternal age at the term of delivery was 29.1 (range, 19–41) years. Conclusion: Middle cerebral artery peak systolic velocity is a highly sensitive non-invasive means for determining the degree of anemia. A Doppler interval of seven days is recommended.

        Key words: fetal anemia, middle cerebral artery peak systolic velocity, Doppler, red cell alloimmunization, intrauterine transfusion