Early menstruation in women is often caused by the following reasons: the first one, insufficient luteal function due to endocrine relations, which causes early menstruation. Secondly, the growth of submucosal fibroids into the uterine cavity causes a relative increase in the area of the endometrium, which affects the contraction of the uterus, causing a shortening of the menstrual cycle, resulting in early menstruation and, clinically, excessive menstrual flow, manifested as irregular vaginal bleeding. Thirdly, the ovarian function declines. During the perimenopause, the menstrual cycle is changed due to the decline of ovarian function, and the menstruation will be early. Fourth, endometrial polyps or inflammation of the endometrium can cause early menstruation. Therefore, if you experience early menstruation, you should go to the hospital for appropriate tests, such as sex hormone test and ultrasound, to find out if there is any organic lesion in the uterus or endocrine disorder, and then give treatment according to the results.