Menstruation is one of the external signs of maturity of reproductive function. The first normal menstruation should be between 9 and 16 years old; the menstrual cycle is the interval between the first two menstrual days, generally in 21 to 35 days, an average of 28 days; the menstrual period is the duration of menstruation, generally in 2 to 8 days; the volume of menstruation in 20 to 60ml, the volume of menstruation more than 80ml, is excessive; menstruation period some women can be accompanied by a slight discomfort performance. Is your menstrual performance consistent with the above, if not, it means that your menstruation is not normal, you need to go to the hospital for examination.