A relatively short period interval of 20 days between cycles is not normal. Normally, a woman’s cycle is between 21 and 35 days. It must be combined with the patient’s other clinical symptoms and signs to analyze the cause comprehensively and deal with the symptoms, for example, if the normal menstruation, 20 days after the appearance of vaginal bleeding again, less is considered not a normal menstruation, may be ovulatory bleeding, because in individual cases women’s cycle can be 34 days. If the patient takes contraceptive pills after menstruation, about 20 days after menstruation is bleeding consider it may be withdrawal bleeding, excluding the existence of special circumstances and triggers, women’s cycle once every 20 days is shortened menstrual cycle, there may be endocrine disorder diseases, there is adenomyosis, uterine fibroids, reproductive tract tumor lesions caused by menstrual disorders, need to carry out relevant examination and treatment.