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 procedure related 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 x 10(9)/L (range, 5.4-96.1 x 10(9)/L) compared with that at the intrahepatic vein (n = 30) 50.9 x 10(9)/L,(range, 29.5-91 x 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.