Uterine spiral arteries in the human placental bed of prolonged pregnancy / 中国病理生理杂志

ABSTRACT

On studying the morphology of spiral arteries in the human placental bed, we found, both in normal term pregnancy and in prolonged pregnancy, there are not only physiological changes such as invasion of trophoblastic cells, disappearance of smooth cells and elastic tissues, but also infiltration of erythrocytes and presence of foam cells in the vessel wall. Since the foam cells are found morphologically very similer to some trophoblastic cells and since the trophoblastic cells have phagocytotic function, we assume that the foam cells may originate from the trophoblastic cells.Besides, we found frequently also thrombosis, thickening of intima and infiltration of abundant erythrocytes in the uterine spiral arteries of prolonged pregnancy. Since these phenomena can diminish blood supply to the placenta, we suppose that they are the main factors leading to placental senescence and to decline in placental functions.