The absence of menstruation is caused by the following reasons. First, and the most common reason, is the menopause caused by endocrine disorders, such as long-term work pressure, often stay up late, irregular life, excessive smoking and drinking can lead to menopause. Second, if a woman of childbearing age has a normal sex life and does not have a period, the first thing to do is to rule out the possibility of pregnancy, then it is recommended to use early pregnancy test paper to detect whether you are pregnant. Third, polycystic ovary syndrome can lead to amenorrhea. Fourth, hyperprolactinemia can also lead to menopause in clinical practice. Fifth, oral contraceptive pills can lead to menstrual failure. Sixth, premature ovarian failure can lead to menopause. Seventh, in case of repeated abortions, causing damage to the endometrium and causing adhesions in the uterine cavity can also cause amenorrhea. Therefore, if the menstruation does not come, it is necessary to check what causes the menopause and then give symptomatic treatment and therapy according to the cause.