ALLOIMMUNE THROMBOCYTOPENIA

Berkowitz RL, Lesser ML, McFarland JG, et al. Antepartum treatment without early cordocentesis for standard-risk alloimmune thrombocytopenia: a randomized controlled trial. Obstet Gynecol 2007;110:249-255 Full Text | Full Text (PDF)

Objective. To evaluate the effectiveness and safety of two antenatal treatment regimens designed to optimally protect fetuses against intracranial hemorrhage resulting from alloimmune thrombocytopenia while minimizing the risks associated with fetal blood sampling.

Methods. In this prospective multicenter study of 73 women with documented alloimmune thrombocytopenia, patients were randomized to receive either intravenous immunoglobulin (IVIG) 2 g/kg/wk (group A) or IVIG 1 g/kg/wk plus prednisone 0.5 mg/kg/d (group B), starting at approximately 20 weeks of gestation. Fetal blood sampling was performed at approximately 32 weeks of gestation, and those with fetal platelet counts less than 30,000/mL(3) were given salvage therapy.

Results. There were two intracranial hemorrhages; neither was due to treatment failure. The average platelet counts at the time of fetal blood sampling were 121,600/mL(3) and 116,100/mL(3), and the average birth platelet counts were 169,400/mL(3) and 134,000/mL(3) for groups A and B, respectively. Twenty-seven percent of patients in group A and 17% in group B received salvage therapy, and only one neonate in each of these subsets had a birth platelet count less than 30,000/mL(3). There were four complications after 79 fetal blood sampling procedures, leading to cesarean deliveries between 32 and 37 weeks. Conclusions. The outcomes of both treatment groups were excellent and comparable. Early cordocentesis is not necessary when treating alloimmune thrombocytopenia in patients who have not delivered an infant with an intracranial hemorrhage in a prior pregnancy.

Comments. This remarkable 35-center-study demonstrates that both of the two suggested treatment regimens for standard-risk alloimmune thrombocytopenia minimize the risk of fetal intracranial hemorrhage. In fact, the documented hemorrhages were PIVH grade I in infants with platelet counts of greater than 100’000/mL³ and therefore not due to treatment failure. Given the fact that the incidence of thrombocytopenia (platelet count < 20’000/mL²) in standard-risk pregnancies complicated by alloimmune thrombocytopenia is close to 50% (Obstet Gynecol 2006;107:91-96), the rates and severity of side-effects of the study interventions are clearly acceptable. TMB

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