Influence of fetal anemia on fetal splenic artery Doppler in Rh-alloimmunized pregnancies.

OBJECTIVE: To verify the correlation between fetal splenic artery Doppler velocimetry and fetal hemoglobin (Hb) levels in Rh alloimmunization. METHODS: Splenic artery Doppler peak systolic velocity (PSV) and pulsatility index (PI) were obtained before cordocentesis in rhesus-alloimmunized fetuses. Doppler was performed before 80 cordocentesis in 36 patients between 20 and 35 weeks of gestation. Mild, moderate and severe anemia were defined as a Hb deficit of >or=2, >or=5 and >or=7 g/dl respectively. RESULTS: Anemia was noted in 64% of the fetuses and moderate and severe anemia in 18 and 21%. Splenic artery PSV was higher in groups with moderate (p = 0.001) and severe (p < 0.000) anemia but not in the group with mild anemia (p = 0.189) when compared to non-anemic fetuses. Splenic artery PI was higher only in the severely anemic group (p = 0.001). CONCLUSIONS: The splenic artery PI and PSV are higher in fetuses with severe anemia.