Serial aggressive platelet transfusion for fetal alloimmune thrombocytopenia: platelet dynamics and perinatal outcome.

Abstract Objectives: Our purpose was to describe the fetal loss rate and platelet dynamics in fetal alloimmune thrombocytopenia managed by serial platelet transfusions. Methods: Retrospective analysis over 10 years of consecutive pregnancies affected by fetal alloimmune thrombocytopenia requiring in utero platelet transfusions. Results: There were 2 perinatal losses in 12 pregnancies managed by 84 platelet transfusions. One was obviously procedure related from exsanguination despite platelet transfusion. The attributable procedurerelated fetal loss rate was 1.2% per procedure but 8.3% per pregnancy. The median rate of fall in fetal platelet count per day after transfusion was lower at the placental cord insertion (n = 54) 40.5 × 10 9 /L (range, 5.4-96.1 × 10 9 /L) compared with that at the intrahepatic vein (n = 30) 50.9 × 10 9 /L,(range, 29.5-91 × 10 9 /L) ( P = .0009). Conclusion: Pooling our results with those previously published yields a cumulative risk of serial weekly transfusions of approximately 6% per pregnancy, indicating the need for development of less invasive approaches. (Am J Obstet Gynecol 2002;186:826-31.)