The Differential Diagnosis of Thrombocytopenia in Pregnancy

Abstract

Background: Thrombocytopenia is, after anemia, the second most common abnormality of the complete blood count in pregnancy, with a reported frequency of 6.6% to 11.2%. It has many causes. Thrombocytopenia should be diagnostically evaluated as early as possible in pregnancy, so that the obstetrical management can be accordingly planned to minimize harm to the mother and child. As the various underlying diseases share clinical features and laboratory findings, the differential diagnosis is often a difficult interdisciplinary challenge.

Methods: In this article, we review pertinent literature (2000-January 2015) retrieved by a selective search in PubMed.

Results: Gestational thrombocytopenia is the most common type, accounting for 75% of cases, followed by severe pre-eclampsia/HELLP syndrome (hemolysis, elevated liver enzymes, low platelet count) in 15-22% and autoimmune thrombocytopenia (ITP) in 1-4%. Gestational thrombocytopenia and ITP differ in the bleeding history, the severity of thrombocytopenia, the frequency of neo - natal thrombocytopenia, and the rate of normalization of the platelet count after delivery. The HELLP syndrome and rarer microangiopathic hemolytic anemias (e.g., thrombotic thrombocytopenic purpura) can be differentiated on the basis of their main clinical features, such as hypertension/proteinuria and upper abdominal pain, the severity of hemolysis and thrombocytopenia, the degree of transaminase elevation, and the rapidity of postpartum remission of the clinical and laboratory findings. A stepwise diagnostic procedure should be followed to distinguish further causes, e.g., to differentiate thrombocytopenia due to infection, autoimmune disease, or drugs from thrombocytopenia due to a rare hereditary disease.

Conclusion: The early interdisciplinary evaluation of thrombocytopenia in pregnancy is a prerequisite for the optimal care of the mother and child. The development of evidence-based recommendations for interdisciplinary management should be a goal for the near future.

Figure 1

Algorithm for the differential diagnosis of thrombocytopenia in pregnancy CMV, cytomegalovirus; DDx, differential diagnosis; DIC, disseminated intravascular coagulation; GT, gestational thrombocytopenia; HBV, hepatitis B virus; HCV, hepatitis C virus; HIV, human immunodeficiency virus; HUS, hemolytic-uremic syndrome; ITP, autoimmune thrombocytopenia; LDH, lactate dehydrogenase; MPV, mean platelet volume; PNH, paroxysmal nocturnal hemoglobinuria; TSH, thyroid-stimulating hormone; TTP, thrombotic thrombocytopenic purpura; vWF, von Willebrand factor; modified from (4).

Figure 2

Platelet aggregation (arrow) in the peripheral blood smear of a patient with classic pseudothrombocytopenia. This laboratory artefact is due to the release of cryptantigens and the binding of antiplatelet autoantibodies when calcium is removed.