Bleeding again after 4 days after endometrial scraping may be related to factors such as activity to expel accumulated blood, uterine cavity residue, endometrial infection, and so on. 1. Activity to discharge accumulated blood: after scraping the endometrium, the patient rests in bed, which leads to the blood in the uterine cavity can not be discharged in time, and the accumulated blood is discharged after activity, which is manifested as vaginal bleeding again. 2. Uterine residue: the endometrium is not completely cleaned up during scraping, there are some uterine residues, when the residual tissue is shed, bleeding symptoms will occur. 3. Endometrial infection: some women may not get enough rest after the operation or do not take anti-inflammatory drugs on time, resulting in endometrial infection, which is manifested as irregular vaginal bleeding and accompanied by abdominal pain, fever and other symptoms. When bleeding occurs again after scraping the endometrium, you should go to the hospital in time for relevant examinations to clarify the cause of the bleeding and then treat it.