The middle cerebral artery peak systolic velocity (MCA- PSV) has been successfully used for timing the first 2 transfusions in fetuses at risk for anemia because of maternal red cell alloimmunization. The Abstract of this study was to assess whether the correlation between the MCA- PSV and fetal hemoglobin is maintained in fetuses that had undergone 2 previous intrauterine transfusions. Study design: Doppler measurement of MCA- PSV was performed before cordocentesis in 39 fetuses. The timing of the third transfusion was based on traditional criteria. The values of MCA- PSV and hemoglobin were expressed as multiples of the median (MoM). Anemia was defined as mild (hemoglobin < 0.84 MoM for a given gestational age, moderate (hemoglobin < 0.65 MoM), and severe (hemoglobin < 0.55 MoM). Regression analysis was used to assess the correlation between the MCA- PSV MoM and fetal hemoglobin MoM. Results: Gestational age at Doppler study ranged from 22 to 35 weeks. Six fetuses (15% ) had normal hemoglobin concentration; 21 (53% ) had mild anemia; 7 (20% ) had moderate anemia; and 5 (12% ) had severe anemia. There was a linear correlation between fetal hemoglobin (y) and the MCA- PSV (x): y = 1.185 - 0.341x. Conclusion: Previously, concerns have been expressed about the accuracy of Doppler prediction of anemia after previous transfusions. Our data suggest that there is a good correlation between the MCA- PSV and fetal hemoglobin in fetuses that have undergone 2 previous transfusions. Our findings expand the clinical situation in which Doppler can be used to monitor red cell alloimmunized pregnancies. The middle cerebral artery peak systolic velocity (MCA-PSV) has been successfully used for timing the first 2 transfusions in fetuses at risk for anemia because of maternal red cell alloimmunization. The Abstract of this study was to assess whether the correlation between the MCA- PSV and fetal hemoglobin was maintained in fetuses that had undergone 2 previous intrauterine transfusions. Study design: Doppler measurement of MCA-PSV was performed before cordocentesis in 39 fetuses. The timing of the third transfusion was based on traditional criteria. The values ​​of MCA- PSV and hemoglobin were expressed as multiples of the median (MoM). Anemia was defined as mild (hemoglobin <0.84 MoM for a given gestational age, moderate (hemoglobin <0.65 MoM), and severe (hemoglobin <0.55 MoM) used to assess the correlation between the MCA-PSV MoM and fetal hemoglobin MoM. Results: Gestational age at Doppler study ranged from 22 to 35 weeks. Six fetuses (15%) had normal h There was a linear correlation between fetal hemoglobin (y) and the MCA-PSV (x) : y = 1.185 - 0.341x. Conclusion: Previously, concerns have been expressed about the accuracy of Doppler prediction of anemia after previous transfusions. Our data suggest that there is a good correlation between the MCA- PSV and fetal hemoglobin in fetuses that have undergone 2 previous transfusions. Our findings expand the clinical situation in which Doppler can be used to monitor red cell alloimmunized pregnancies.