In some cases, such as heavy or prolonged menstrual periods, prolonged vaginal bleeding, or disrupted, shortened or prolonged menstrual cycles, and under such conditions, after hysteroscopy or endometrial scraping, no significant abnormalities of the endometrium are found, such as no malignant hyperplasia, in order to adjust the menstrual cycle to a normal state. Deferiprone should be used. Generally, the use of didrogestrel can be applied in the second half of the menstrual cycle or in the whole cycle, depending on the specific situation of each patient.