Normal menstrual cycle is about 28 days, advance or delay within 7 days, also regarded as normal. If the menstrual cycle is 20 days and occurs once in a while, it is considered to be due to the recent diet is too greedy for cold, drinking cold, too nutritious, too much stress, poor rest and other reasons, resulting in transient menstrual disorders, which can be alleviated through diet, life and other adjustments. If menstruation is early for a long time, it can be regarded as frequent menstruation, and the following reasons are considered: First, adolescent women, due to the development of ovarian function is not yet complete, menstruation will be disordered and the cycle is not fixed. Second, menopausal women, due to the gradual shrinkage of the ovaries, the function is gradually reduced, the body’s hormone secretion level is abnormal, will also lead to menstruation more or less, the cycle is not regular. Thirdly, women of childbearing age may suffer from luteal insufficiency, gynecological inflammation and other diseases.