Normal menstruation is regular, expressed in terms of cycle, period and volume. The volume of menstruation is usually between 20-80mL, less than 5mL is called hypomenorrhea. There are many reasons for menorrhagia, such as stressful work, mood swings, late nights, poor rest, etc., which can cause menorrhagia, and after uterine operations, such as abortion, curettage, etc., the cervical cavity or the uterine cavity may have adhesions, and the flow of menstrual blood may not be smooth, which can cause menorrhagia, accompanied by symptoms of dysmenorrhea. If the endometrial layer is damaged, it may also cause menorrhagia. If the endometrium is infected with tuberculosis, it can damage the endometrium and cause scanty menstruation. There is a relationship between menstrual flow and the thickness of the endometrium, which depends on estrogen for its proliferation. When the ovarian function decreases, the estrogen level decreases, which affects the proliferation of the endometrium, and the menstrual flow naturally decreases. In addition, hypermenorrhea can also occur in cases of hyperprolactinemia and polycystic ovary syndrome.