What Role Do Blood Vessels Play in the Menstrual Cycle?
During the menstrual cycle, blood vessels in the endometrium (the lining of the uterus) go through cyclic changes. In the proliferative phase, estrogen stimulates the growth of the endometrium and its blood vessels. During the secretory phase, progesterone enhances the development of spiral arteries. When implantation does not occur, the withdrawal of these hormones leads to the breakdown of the endometrial lining and the shedding of blood vessels, resulting in menstruation.
