Intervillous Thrombosis

Abstract

Coagulation of blood within the intervillous space may result in a variety of pathologic lesions, most of which have a laminated appearance and are commonly referred to as thrombi, haematomas or thrombohaematomas. Specific lesions include intervillous thrombus, subchorionic intervillous thrombus, massive subchorionic thrombohaematoma, basal intervillous thrombus, rounded intraplacental haematoma and basal plate plaque. These lesions have multiple potential aetiologies relating to the classical causes of coagulation (stasis, endothelial injury, hypercoagulability), including haemorrhage from fetal capillaries, stasis or abnormal flow of maternal blood (e.g., in severe villous oedema, during labour or in the subchorionic zone), maternal hypercoagulability and maternal hypertensive disease. As such, their clinical implications also vary widely depending on the specific diagnosis. In this chapter, the aetiology, nosology, epidemiology, macroscopy, microscopy and clinical associations of the above lesions are discussed.