Under normal circumstances, menstruation will be clean in 3-7 days, if the duration of menstruation is more than 9 days, it is an abnormal phenomenon, which is often caused by the following reasons: 1) endocrine disorders, such as estrogen deficiency makes it difficult to repair the endometrium, so menstruation will be prolonged. 2) inflammation of the endometrium or the presence of polyps can lead to menstrual dribbling. 3) because of the presence of submucosal fibroid, clinically it will lead to poor uterine contraction, so it will make menstrual blood prolonged. 4) because of cancer of the endometrium, endometrial complex hyperplasia or atypical hyperplasia. If there is a sub-mucosal fibroid, it will lead to poor contraction of the uterus, so it will prolong the time of menstrual bleeding.4. Because of endometrial cancer, endometrial complex hyperplasia or atypical hyperplasia, it will lead to prolonged menstrual bleeding. Therefore, it is recommended to do detailed examination, and if necessary, diagnostic scraping is needed, and clinicopathologic diagnosis will prevail, and then treatment will be given.