Regulation of angiogenesis in the endometrium

A crucial stage in pregnancy is the implantation of the embryo into the end ometrium. The endometrium, wh ich is situated in the lining of the uterus, is a complex structure consisting of a single epithelial layer overlying a mesenchymal stroma. Cyclical growth of the endometrium under the influence of ovarian steroids results in the establishment of a receptive endometrium . If implantation fails, or is deliberately prevented by the use of fertili ty regulation, the endometrium is shed by the process of menstruation. This unique system of cyclic tissue regeneration is dependent on the cyclical g rowth and regression of the blood vessels that supply the endometrium. Litt le attention has been paid to this crucial aspect of human reproduction but it now appears that many disorders that reduce the quality of life of mode rn women, such as heavy menstruation, endometriosis, breakthrough bleeding and infertility, might have their basis in disorders of the endometrial vas culature.