There are many reasons why there is still a small amount of blood after menstruation, which may be caused by uterine diverticulum, endometrial polyp, uterine fibroids, cervical diseases and so on. 1. Uterine diverticulum: women who have had a cesarean section, due to poor healing of the uterine incision and other factors, may form a small cavity in the incision site and the uterine cavity, during menstruation, blood will accumulate in the cavity, and after menstruation, menstrual blood will continue to be discharged from the uterine cavity in the cavity, which will result in a small amount of blood after menstruation is clean. 2. Endometrial polyps: due to inflammatory stimulation or excessive hormone levels in the body and other factors, resulting in excessive growth of the female endometrium, the uterine cavity localized tissue hyperplasia, resulting in the formation of polyps. Uterine polyps will affect the contraction of the uterus during menstruation, so that the endometrial shedding is incomplete, or the polyp itself bleeds, which will prolong the menstruation period and the above symptoms. 3. Uterine fibroids: uterine fibroids, such as submucous fibroids, or larger interstitial fibroids, will affect the uterine contraction during menstruation, resulting in the uterine blood sinuses can not be closed, so that the period is prolonged, and there will be a small amount of bleeding after the period is clean. 4. Cervical diseases: Cervical diseases, such as cervical polyps, cervical inflammation, cervical lesions, cervical cancer, etc., will also appear irregular bleeding symptoms at the site of the disease, and the local tissues are congested during the menstrual period, which will increase the possibility of bleeding, and thus the above symptoms will appear. If there is a small amount of vaginal bleeding after menstruation, it is recommended to consult a doctor in time to avoid delaying the condition.