It is normal for girls to have a period of 3-7 days, and the duration of the period varies for each person, so as long as it is within this range there is no need to worry. Menstruation less than 3 days or more than 8 days are abnormal phenomena, may be anemia, cold caused by the uterine cold, as well as qi stagnation and blood stasis caused by low menstrual flow, short menstrual period, there are uterine fibroids, endometriosis, endometrial hyperplasia easy to cause menstrual blood flow, prolonged menstrual period. Frequent use of contraceptive pills, staying up late and excessive mental stress can also affect the amount and duration of menstruation. If there is a change in the number of days of menstruation, it is necessary to go to the hospital for a comprehensive examination, and then make reasonable adjustments under the guidance of the doctor after ascertaining the situation. During menstruation, pay attention to abdominal warmth, can not eat cold, stimulating food, and can not eat blood-activating drugs, it is best to pay attention to menstrual hygiene, to avoid gynecological infections.