563 Nucleated red blood cells in the human placenta

OBJECTIVE: To determine the perinatal outcome in severe red-cell fetomaternal alloimmunization treated with intravenous fetal exchange transfusion (IFET) before 22 weeks of gestation (WG), and to investigate the predictability of fetal anemia before cordocentesis.STUDY DESIGN: Retrospective cohort study of fetuses treated between January 1996 and December 2000.Severity was predicted fi'om the past obstetrical history, initial maternal antibody level and serial ultrasound examination.The main outcome measures were the degree of fetal anemia and perinatal outcome.Results are expressed as mean _+ SD.RESULTS: Data from 32 pregnancies in 27 women were recorded.The previous perinatal loss rate was 55.5% when excluding first pregnancies.Anti-D antibody was present in 25 cases and anti-Kell in 3 cases.The first IFET was performed at 19.8 _+ 1.8 WG.All fetuses were severely anemics (4.5 _+ 2.7 g/dl), and hemoglobin levels were not different between 20 hydropic and 12 nonhydropic fetuses (4.1 _+ 2.5 vs. 5.6 -+ 2.8 g/dl, P= .33).The initial nmternal anti-D level ranged from 4 to 76 gg/ml but was not correlated to fetal anemia.Alter first IFET, hemogloglobin level was significantly increased (12.0 +-2.7 g/dl, P< .0001),and the second transfusion was performed 1 to 2 weeks after.The 30 remaining fetuses underwent 148 transfusions during pregnancy (IFET: 123, intraperitoneal transfusion: 25).The fi~tal loss rate was 18.8%.Twenty-six infants were delivered at 35.2 -+ 1,4 WG, birth weight was 2529 _+ 508 g, hemoglobin level 11.3 _+ 3.1 g/dl.Eighteen infants required exchange transfusion, and one neonatal death occurred.CONCLUSION: The overall smwival rate was 78%, significantly higher than the previous perinatal loss rate .Past obstetrical history, initial maternal antibody level, and decreased fetal movements at biweekly ultrasound evaluation were the only predictive markers of severity.