Can we predict neonatal thrombocytopenia in offspring of women with idiopathic thrombocytopenic purpura?

Background: We aimed to investigate which factors in the clinical profile of mothers with idiopathic thrombocytopenic purpura (ITP) can predict neonatal risk of thrombocytopenia. Methods: Data was retrospectively collected from all pregnant women with ITP who presented to our institution between 2001 and 2013. Neonatal offspring of these women were classified into 2 groups based on the presence or absence of neonatal thrombocytopenia (platelet count <100×10⁹/L). Several parameters were compared between the 2 groups, including maternal age, maternal platelet count, maternal treatment history, and thrombocytopenia in siblings. We further examined the correlation between maternal platelet count at the time of delivery and neonatal platelet count at birth; we also examined the correlation between the minimum platelet counts of other children born to multiparous women. Results: Sixty-six neonates from 49 mothers were enrolled in the study. Thrombocytopenia was observed in 13 (19.7%) neonates. Maternal treatment for ITP such as splenectomy did not correlate with a risk of neonatal thrombocytopenia. Sibling thrombocytopenia was more frequently observed in neonates with thrombocytopenia than in those without (7/13 vs. 4/53, P<0.01). No association was observed between maternal and neonatal platelet counts. However, the nadir neonatal platelet counts of first- and second-born siblings were highly correlated (r=0.87). Conclusion: Thrombocytopenia in neonates of women with ITP cannot be predicted by maternal treatment history or platelet count. However, the presence of an older sibling with neonatal thrombocytopenia is a reliable risk factor for neonatal thrombocytopenia in subsequent pregnancies.