ULTRASONOGRAPHIC FETAL SPLEEN MEASUREMENTS IN RED-BLOOD-CELL ALLOIMMUNIZED PREGNANCIES

OBJECTIVES: This study was performed to evaluate the possible relation ship between fetal spleen size and fetal hemoglobin levels and to asse ss the predictive value of ultrasonographically measured fetal spleen size as an estimate of the severity of fetal hemolytic anemia. STUDY D ESIGN: Before 85 consecutive fetal blood samples in 28 red blood cell- alloimmunized pregnancies ultrasonographic fetal spleen measurements w ere performed. Results were compared with our own longitudinally deriv ed reference ranges and were correlated with fetal hemoglobin deficit. RESULTS: A significant positive correlation was found between spleen perimeter and fetal hemoglobin deficit. The ultrasonographic finding o f splenomegaly correctly predicted severe fetal anemia (hemoglobin def icit > 5 SD from normal mean) in 44 of 47 cases, a positive predictive value of 94%. At first transfusion ail fetuses showing splenomegaly w ere severely anemic. CONCLUSION: Fetal spleen measurements may be a us eful adjunct to ultrasonographic evaluation in the management of sever e red blood cell-alloimmunized pregnancies.