Menstruation 15 days late has not come the main reasons are: 1, pregnancy, have a normal sex life, in the process of sex without contraception, the body has the conditions of conception, may be early pregnancy symptoms, it is recommended to use a pregnancy test paper test, if positive to the regular hospital to do a detailed examination. 2, amenorrhea, such as has reached menopause, the decline in ovarian function will be prone to delayed menstruation, amenorrhea, manifested as Low menstrual flow, easy to fatigue, poor skin condition, emotional recurrence, etc., can be adjusted through traditional Chinese medicine and dietary system, regular life and work and rest.3, stress, malnutrition, bad life and dietary habits, work intensity, stress, irregular work and rest, long-term hunger or overeating easily affect the endocrine, menstrual disorders, menstruation is delayed, the body has a low immune system, which may cause a variety of diseases.4, taking weight-loss drugs or emergency contraceptive devices, or the use of emergency contraceptive devices, or the use of emergency contraceptive devices, or the use of emergency contraceptive devices, can cause a variety of diseases. The use of weight-loss drugs or emergency contraceptives affects the ovarian function, leading to endocrine disorders and menstrual disorders.