Management of thrombotic microangiopathy in pregnancy and postpartum: report from an international working group

Pregnancy and postpartum are high-risk periods for different forms of thrombotic microangiopathy (TMA). However, the management of pregnancy-associated TMA remains ill defined. This report, by an international multidisciplinary working group of obstetricians, nephrologists, hematologists, intensivists, neonatologists, and complement biologists, summarizes the current knowledge of these potentially severe disorders and proposes a practical clinical approach to diagnose and manage an episode of pregnancy-associated TMA. This approach takes into account the timing of TMA in pregnancy or postpartum, coexisting symptoms, first-line laboratory workup, and probability-based assessment of possible causes of pregnancy-associated TMA. Its aims are: to rule thrombotic thrombocytopenic purpura (TTP) in or out, with urgency, using ADAMTS13 activity testing; to consider alternative disorders with features of TMA (preeclampsia/eclampsia; hemolysis elevated liver enzymes low platelets syndrome; antiphospholipid syndrome); or, ultimately, to diagnose complement-mediated atypical hemolytic uremic syndrome (aHUS; a diagnosis of exclusion). Although they are rare, diagnosing TTP and aHUS associated with pregnancy, and postpartum, is paramount as both require urgent specific treatment.