An endometrial lining of about 10mm on the twelfth day of menstruation does not necessarily require diagnostic scraping, and the decision needs to be made according to the condition. Generally speaking, on the twelfth day of menstruation, women are in the late stage of endometrial proliferation, and the thickness of the endometrium is mostly around 6mm, so the endometrial thickness of 10mm in this period is relatively too thick. This situation does not always need to do diagnostic scraping, if the endometrium is found to be unevenly thickened under ultrasound observation, or at the same time there is no irregular vaginal bleeding, you can consider scraping to find out whether there is a lesion in the endometrium, but also through the hysteroscopy to get a general understanding of the condition first. If the endothelial thickening is more uniform, and there is no bleeding and other abnormal manifestations can be followed up and observed, and if necessary, diagnostic scraping can be taken. It is recommended to consult a doctor in time to standardize the diagnosis and treatment.