Aunt that is menstruation, menstruation after the onset of menstruation usually 3-7 days, the specific time can not be generalized, need to be based on women’s living habits, dietary habits and other factors to determine. If the duration of the period is usually the same, then no intervention is needed. If the period is suddenly lengthened or shortened, it is necessary to consult a doctor in time to clarify the presence of uterine adhesions, endometrial polyps and other diseases. Menstruation is a normal physiological phenomenon in which the endometrium of the uterus proliferates and sheds under the changes of the ovaries after the ovaries have matured, accompanied by vaginal bleeding. Normal menstruation lasts for 3-7 days. However, due to the large individual differences between different women, so the specific menstrual days can not be generalized. First of all, menstruation is obviously related to the hormone levels in a woman’s body. If a woman has an irregular lifestyle or is in a state of prolonged stress, it will lead to endocrine disorders, and the duration of menstruation may be suddenly shortened or lengthened. In addition, endometrial polyps, uterine fibroids, adenomyosis and other diseases can lead to prolonged menstrual periods, increased menstrual flow, dysmenorrhea, irregular uterine bleeding, etc. Polycystic ovary syndrome and other diseases can lead to scanty menstruation, irregular menstruation or even amenorrhea, which requires prompt medical attention to clarify the condition and then treat it in a timely manner. To summarize, menstruation usually lasts between 3-7 days. Sudden shortening or lengthening of menstruation period, sudden increase or decrease of menstrual flow may be caused by irregular life and routine, or may be caused by related diseases, so it is recommended to consult a doctor for examination in time and take timely treatment.