Vacation refers to menstruation. Menstruation twice a month may be due to physiological reasons such as short menstrual cycle, or may be caused by endocrine disorders, endometrial polyps and other pathological reasons, which need to be analyzed specifically. 1. Physiological reasons: the average menstrual cycle is 28 days, but there are also women who have short menstrual cycles, resulting in two menstrual periods a month. 2. Pathological reasons: irregular life and work, improper diet, high mental tension and other reasons may lead to endocrine disorders, causing abnormal uterine bleeding, resulting in twice a month menstruation. If the patient suffers from endometrial polyps, cervical polyps and other diseases, there may also be non-menstrual vaginal bleeding, manifested in two menstrual periods a month. There may be other reasons for menstruation twice a month, so it is recommended to go to the hospital for a gynecological examination to determine the cause of the problem and then treat the symptoms.