Mineralization of Trophoblast Basement Membrane

Abstract

Sedimentation of minerals, specifically calcium phosphate and iron as haemosiderin, along the basement membrane of the chorionic villus results in blue-purple discolouration of the trophoblast basement membrane (TBM). This phenomenon may be seen in fibrotic avascular villi in livebirths and is prominent in stillbirths. It is also observed in villi with normal-looking vasculature, especially in aneuploidy, malformation syndromes, polyhydramnios, fetal hydrops and more. Genetic disorders of calcium and iron metabolism, such as Bartter syndrome and thalassaemia, frequently exhibit TBM mineralization.