If you are bleeding again within a few days after menstruation and the color is black, you may consider that it is caused by ovulation bleeding, cervical disease, endometrial disease and so on. 1. Ovulation bleeding: not a few days after the menstrual period is considered to enter the ovulation period, some women in the ovulation period due to the estrogen level of a transient decline, there will be a small amount of endometrial shedding, manifested as bleeding, due to the small amount of bleeding, oxidation occurs in the process of discharging, so the color of black. 2. Cervical diseases: cervicitis, cervical polyps, cervical squamous intraepithelial lesions and cervical cancer and other cervical diseases can lead to localized congestion, edema and erosion, resulting in contact bleeding or irregular bleeding. 3. Endometrial diseases: endometrial polyps, uterine fibroids, endometrial cancer and other diseases will affect the endometrium, which will lead to abnormal local coagulation fiber regulation mechanism of the endometrium and irregular vaginal bleeding. There are many reasons for bleeding within a few days after menstruation, so it is recommended that patients go to the hospital for a detailed examination and targeted treatment under the guidance of the doctor.