A woman’s menstrual cycle is between 21-35 days, with an average of 28-30 days. A period of less than 21 days is called frequent menstruation, and a period of more than 35 days is called sporadic menstruation. Periods of 3-7 days and menstrual volume of 20-60 ml are normal. When menstruation is new, the gonadal axis is unstable and the hormones secreted by the ovaries are unbalanced, so menstrual disorders such as early, late or prolonged periods may occur. If the menstrual period lasts more than 7 days, the volume of menstruation exceeds 80ml with irregular cycles, heavy bleeding or even serious anemia, these are all signs of anovulatory dysfunctional uterine bleeding. Of course it is on the condition that organic diseases are excluded, such as pregnancy-related diseases, genital tumors, internal hematologic diseases, etc. As the gonadal axis develops, menstruation will gradually become regular. It is important to maintain a regular life, avoid staying up late and avoid stimulation by cold.