Premature menstruation is mainly caused by changes in hormone levels in the body. The formation of menstruation is mainly due to the sudden drop of estrogen and progesterone, which leads to endometrial exfoliation resulting in bleeding and the discharge of endometrium. If your menstruation was normal in the past and suddenly it is early for more than a week, it may be a manifestation of decreased ovarian function; from the perspective of Chinese medicine, spleen qi deficiency and kidney qi deficiency can cause early menstruation. During menstruation, take rest and avoid straining, quit smoking and drinking, eat less cold food to prevent menstrual discomfort or prolonged periods, avoid sexual intercourse, change underwear and sanitary napkins regularly to avoid reproductive system infections. Menstrual blood is a good culture medium for bacteria and viruses, which can easily breed bacteria and lead to reproductive system infections, and in serious cases, may lead to adhesions of the fallopian tubes and uterus, resulting in infertility.