A prolonged menstrual period of about half a month indicates that the following conditions may exist: the first condition of abnormal uterine bleeding; the second condition of uterine fibroids; and the third condition of adenomyosis. These three conditions are the most likely diseases to cause a prolonged menstrual period. The normal onset of menstruation depends on the normal function of the hypothalamic-pituitary-ovarian axis, and when there is a problem with any of them, it may cause endocrine disruption, which may lead to abnormal uterine bleeding. The second cause is uterine fibroids, which can increase the size of the entire uterus and enlarge the uterine cavity, leading to prolonged menstruation. Another condition is adenomyosis, which can also increase the size of the uterus and enlarge the area of the endometrium, leading to prolonged or excessive menstruation. The diagnosis of fibroids and adenomyosis can depend on a gynecological ultrasound, while abnormal uterine bleeding can be detected by a blood test for hormone 6, based on the results of which you will know which aspect of the condition you are in.