Diagnostic scraping must be done in the following cases: 1. Diagnostic scraping is required if the menstrual period does not clear for more than nine days and the clinical treatment with medication does not stop the bleeding. 2. Diagnostic scraping must be done if the endometrium is found to be abnormally thickened and there is suspicion of endometrial lesions. 3. If the vaginal bleeding is prolonged and the ultrasound reveals uneven echogenicity of the endometrium, diagnostic scraping must also be done. The purpose of diagnostic scraping is to send the scraped tissue for pathological examination, and then give the necessary treatment according to the results of the pathological diagnosis, in addition to diagnostic scraping to exclude the possibility of malignant changes in the endometrium.