How to evaluate and treat the spectrum of TMA syndromes in pregnancy

Abstract

Thrombotic microangiopathy (TMA) is the broad definition for thrombocytopenia, microangiopathic hemolytic anemia, and end-organ damage. Two important categories are thrombotic thrombocytopenic purpura (TTP) and complement-mediated hemolytic-uremic syndrome (CM-HUS). Pregnancy and the immediate postpartum period are associated with TMAs specific to pregnancy in rare situations. These include pregnancy-induced hypertension, preeclampsia, and hemolysis, elevated liver enzymes, and low platelets. TTP and CM-HUS may present in pregnancy. However, the diagnosis may not be immediately obvious as they share characteristics of pregnancy-related TMAs. Within this review, we discuss investigations, differential diagnosis of TMAs in pregnancy, and management. The importance is a risk of maternal mortality but also poor fetal outcomes in relation to TTP and CM-HUS. Treatment of these disorders at presentation in pregnancy is discussed to achieve remission and prolong fetal viability if possible. In subsequent pregnancies, a treatment pathway is presented that has been associated with successful maternal and fetal outcomes. Critical to this is a multidisciplinary approach involving obstetricians, the fetal medicine unit, and neonatologists.