Menstruation is medically known as menstruation, which is the cyclical shedding of the uterine lining with bleeding due to cyclical changes in the ovaries. The duration of each menstruation is known as the menstrual period, which is usually 2-8 days, with an average of 4-6 days. There are also a few people with the end of the period, the blood gradually reduced to disappear, so the period can be relatively longer. The amount of menstruation and the color of the blood can also be used to determine whether menstruation is normal or not. The amount of menstrual flow is the total amount of blood lost during a period, which is normally 20-60 ml, and more than 80 ml is considered to be an increase in the amount of menstrual flow. The color of menstrual blood is dark red, mostly endometrial debris, cervical mucus and shed vaginal epithelial cells. According to the above to determine whether the menstrual period is normal or not, if there is any discomfort, please go to the regular hospital in a timely manner, after the examination to determine whether there is any disease, so as not to delay the condition.