Risk factors for neonatal thrombocytopenia in pregnancy complicated by idiopathic thrombocytopenic purpura

The aim of this study was to evaluate risk factors for the occurrence of fetal/neonatal passive immune thrombocytopenia (PIT) in pregnancy complicated with ITP. We studied 52 pregnancies with ITP and the 54 neonates retrospectively. Neonatal platelet counts were compared with maternal platelet counts, platelet-associated IgG (PAIgG) values and the presence of antiplatelet antibody in maternal circulation, history of previous PIT, maternal treatments for ITP, and other maternal/neonatal factors including gestational age and birth weight. Logistic regression analysis for multivariables was performed. PIT (platelet counts < 100 x 10(3)/microl) without neonatal mortality or any morbidity was observed in eight (15.4%) of 52 pregnancies. The presence of circulating antiplatelet antibodies in maternal blood, splenectomy prior to pregnancy, and a history of previous PIT were observed more frequently with statistical significance in women giving birth to neonates who developed PIT. By logistic regression analysis, splenectomy prior to pregnancy was found to be the single significant variable (p=0.017, odds ratio 9.33) among the risk factors for PIT. Thus, splenectomy prior to pregnancy is related to increased risk for PIT in ITP-complicated pregnancy.