If menstruation comes and doesn't go, it is often caused by the following reasons: First, common endocrine disorders, such as difficulty in repairing endometrium under the condition of insufficient estrogen, make vaginal bleeding stop. Second, due to submucous myoma of uterus, the area of uterus relative to endometrium increases, which affects uterine contraction and prolongs menstrual time. Third, inflammation of the endometrium, or polyps in the endometrium, can also make menstruation difficult to clean. Fourth, menstruation may not be easy to clean because of pelvic tumors or endometriosis. Therefore, if menstruation has been unclean for more than 9 days, you must do a detailed examination. According to the reasons, the corresponding treatment methods are given.