Vascular changes in placentae from cases of materno-fetal rhesus incompatibility.

Three placentae from cases of materno-fetal Rhesus incompatibility have been studied electron microscopically. An abnormal villous vascular arrangement with dilated capillaries and newly formed vessels and stromal edema were the most characteristic findings. Syncytiotrophoblastic trophic changes and focal thickening of the trophoblast basement membrane were also found. It is suggested that placental changes observed in Rh incompatibility could be related to endothelial cell damage.