Thrombocytopenia in pregnancy

Thrombocytopenia is a common hematologic problem in pregnant women. The most common cause of thrombocytopenia is gestational thrombocytopenia, which is usually mild, is not associated with bleeding or neonatal thrombocytopenia, and resolves spontaneously postpartum. Gestational thrombocytopenia, however, may be hard to discern from immune thrombocytopenia (ITP), another cause of isolated thrombocytopenia during pregnancy, although thrombocytopenia due to ITP is often more severe and occurs earlier in pregnancy. Preeclampsia is the most common medical disorder of pregnancy and is associated with a constellation of symptoms including hypertension and proteinuria; thrombocytopenia is generally mild, but reflects the severity of underlying preeclampsia. The syndrome of hemolysis, elevated liver enzymes and low platelets (HELLP) is thought by some to be a variant of preeclampsia as it shares some manifestations but also displays unique ones, particularly liver involvement and microangiopathic hemolytic anemia. HELLP may be difficult to discern from primary thrombotic microangiopathies such as thrombotic thrombocytopenic purpura (TTP) and the atypical hemolytic uremic syndrome (aHUS), which are not unique to pregnancy but occur with increased frequency in this setting. Accurate diagnosis of the cause of thrombocytopenia during pregnancy is important, as treatment varies depending on the etiology. Careful consideration of the timing of onset of thrombocytopenia, and associated hematologic and other manifestations, needs to be considered in the differential diagnosis. Though thrombocytopenic disorders may severely compromise the outcomes of some pregnancies, prompt diagnosis and appropriate therapy often lead to successful pregnancy outcomes.