Prediction of fetal anemia by Doppler of the middle cerebral artery and descending thoracic aorta

Background Despite significant advances, perinatal hemolytic disease has not been eradicated and is still associated with significant morbidity and mortality, especially in developing countries. An accurate method for antenatal diagnosis and quantification of fetal anemia is a crucial step prior to the performance of invasive procedures, which are not risk-free. The middle cerebral artery peak systolic velocity (MCA-PSV) is currently the most popular non-invasive diagnostic method used to quantify fetal anemia and determine the exact timing for transfusion The combined use of MCA-PSV and descending thoracic aorta mean velocity (DTA-MV) has not been previously evaluated. Since this strategy has the potential to decrease false positive results it could reduce unnecessary cordocenteses, therefore minimizing fetal risks. This study aimed to evaluate the accuracy of MCA-PSV associated with DTA-MV in the prediction of fetal anemia. Method Retrospective analysis of 90 cordocenteses performed on alloimmunized pregnancies in a single hospital MCA-PSV and DTA-MV were performed immediately before cordocentesis. The Dopplervelocimetry findings were compared with fetal hemoglobin concentration. Sensitivity, specificity, positive and negative predictive values and accuracy of MCA-PSV and DTA-MV in the prediction of moderate/severe fetal anemia were calculated. Results The individual sensitivity of MCA-PSV and DTA-MV was 100 and 95.7%, specificity was 65 and 100% and accuracy was 92.2 and 96.7%, respectively. The combination of both vessels produced a higher overall accuracy (98.6%). Conclusion MCA-PSV is more sensitive and DTA-MV is more specific in the detection of fetal anemia. The highest diagnostic accuracy was obtained by the association of both Doppler evaluations.