A normal person’s menstrual flow is usually between 20ml and 60ml, and the menstrual period usually lasts from 2 to 8 days, with an average of 4 to 6 days. In normal menstruation, the total amount of menstruation at one time is between 20ml~60ml, menstruation less than 20ml is regarded as oligomenorrhea, which is mostly due to the thin uterine lining and less bleeding, menstruation more than 80ml is regarded as hypermenorrhea, which may be due to the excessive proliferation of the uterine lining, and also need to be vigilant for fibroids, coagulation dysfunction and other factors. Menstruation may come early or late depending on individual circumstances, and the period usually lasts 2-8 days, with an average of 4-6 days. If menstruation is not cleared for a long time, timely examination is needed to find the cause of the disease and timely treatment.