ITP (immune thrombocytopaenic purpura) and pregnancy

• immune thrombocytopenic purpura (ITP) is caused by platelet destruction in the reticular endothelial system, due to platelet auto-antibodies against several platelet membrane glycoprotein complexes
  • ITP is characterized by a moderate to severe decrease in the platelet count - approximately 5% of cases of thrombocytopenia in pregnancy are due to ITP
  • ITP requires monitoring during pregnancy and after delivery, and may require treatment, due to the higher risk of maternal hemorrhage when the platelet count is low
  • there is a minor risk of thrombocytopenia in the newborn - the overall risk of neonatal thrombocytopaenia in an infant born to a mother with ITP who has a platelet count of < 50x10 ^9/L is 6-10%
  • unfortunately, there is currently no confirmatory diagnostic test to definitively distinguish ITP from GT (gestational thrombocytopaenia) in otherwise healthy pregnant women presenting with thrombocytopenia
    • ".. the true diagnoses of these two conditions largely become evident in retrospect, after delivery. However, it has to be noted that the delayed recognition of the unwanted disorder and the lack of advance appropriate intervention can, then, potentially jeopardize the final outcome of the mother or the newborn.."(1)
      • thrombocytopenia detected within 28 weeks of pregnancy and platelet counts of less than 50 × 10^9/L at initial presentation are the most important predictive factors for ITP in pregnant women (1)

Reference:

• (1) Kwon JYet al. Predictors of idiopathic thrombocytopenic purpura in pregnant women presenting with thrombocytopenia. International Journal of Gynecology & Obstetrics 2007; 96 (2):85-88.
• (2) Kelton JG. Idiopathic thrombocytopenic purpura complicating pregnancy. Blood Reviews 2002; 16 (1):43-46.