The association of pregnancy with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome.

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome occurs more commonly in women and among women is commonly associated with pregnancy. Case series of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome from 1964 to 2002 were reviewed (1) to document the reports of occurrence of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome during pregnancy and (2) to search for reports of women with congenital or familial thrombotic thrombocytopenic purpura-hemolytic uremic syndrome who were initially diagnosed during their first pregnancy. The time during pregnancy with greatest risk for development of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome is near term and during the postpartum period. This is also the time of greatest risk for thrombotic events and for the occurrence of other pregnancy-related syndromes: preeclampsia, eclampsia, and hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome. These other syndromes may also be associated with thrombocytopenia, microangiopathic hemolytic anemia, neurologic symptoms, and renal insufficiency, making their distinction from thrombotic thrombocytopenic purpura-hemolytic uremic syndrome difficult or impossible. The occurrence of preeclampsia and related syndromes, the hypercoaguable state that occurs in late pregnancy and postpartum, and the progressively decreasing concentration of ADAMTS13 that occurs during late pregnancy may combine to increase the risk for occurrence of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome.