Fetal hydrops and middle cerebral artery Doppler in prediction degree of fetal anemia and the best timing for therapy.

PURPOSE: To determine the role of fetal multiples of the median of middle cerebral artery peak systolic velocity (MoM MCA-PSV), in predicting the degree of fetal anemia for determination of the best timing for the second intrauterine intravascular transfusion (IUIVT) in hydropic fetuses with Rh alloimmunization. MATERIALS AND METHODS: Prospective study of 30 monofetal pregnancies with maternal Rh D alloimmunization and hydrops fetalis, from 2005 to 2012 that underwent first and second IUIVT were assessed. RESULTS: Thirty IUIVT were performed at 26.9 weeks (standard deviation, SD 4.3). Mean interval to the second procedure was 11.23 (SD 6.21) days and average hematocrit decline rate was 1.45%/day. The study did not demonstrated statistical significance between MCA-MoM-3 before the second IUIVT, and the mean decline rate in fetal hematocrit levels (expressed in percentage/day) r = 0.220; p = 0.242, and between MCA-MoM-3 and the time interval between both procedures (T) r = -0.157; p = 0.408. CONCLUSION: The measurements fetal MoM-MCA before every IUIVT cannot be useful as predictor for the best timing for the next IUIVT, but it can be useful in predicting severity of fetal anemia.