Villous basement membrane thickening and fibrinoid necrosis in normal and abnormal placentas

The association between two placental lesions—fibrinoid necrosis of villi and trophoblastic basement membrane thickening—is described. The two lesions are often found together in villi in normal placentas. There is a higher incidence of both in pre-eclampsia, intrauterine growth retardation, and in placentas associated with intrauterine death. The evidence that these villous changes may be a manifestation of an immune reaction is examined and other possibilities are considered.