If menstruation is always one week early, it may be caused by the following reasons: First, there are problems with the endometrium, such as endometrial inflammation or endometrial polyps, which may cause early menstruation. Second, caused by luteal insufficiency. For some reason, the corpus luteum atrophies early, so menstruation is always one week early. Thirdly, because of submucosal fibroids of the uterus or large fibroids between the walls of the uterus, causing menstruation to be one week early, under normal circumstances, the menstrual cycle should not be less than 25 days, it is recommended to actively go to the hospital to do the corresponding examination, such as sex hormone six laboratory tests, ultrasound examination, through the examination, according to the results of treatment, otherwise this situation in the clinical, may cause early menopause.