This is due to the fact that the ovarian function of the woman is gradually declining at this time and the follicles are gradually depleted. The remaining follicles are less responsive to the woman’s follicle stimulating hormone, so the follicles cannot develop and mature and the ovaries cannot ovulate. The absence of ovulation leads to a lack of progesterone in women, so the endometrium is merely estrogenic and exhibits varying degrees of hyperplasia. Since there is no progesterone to turn the endometrium into a secretory phase, the endometrium will continue to thicken and the patient will show clinical manifestations of heavy menstrual flow with large blood clots. Pathological examination can reveal endometrial hyperplasia, and in some patients, even complex hyperplasia.