Menstruation can occur without ovulation. Menstruation is an important sign of maturity of female reproductive function. Under normal circumstances, female menstruation is cyclical and self-limiting. The lining of the uterus will shed and bleed periodically in response to the ovarian cycle, resulting in menstruation. Anovulatory menstruation usually occurs during puberty or perimenopause. Girls who have just entered puberty may experience anovulatory menstruation due to the underdevelopment of the hypothalamus, pituitary gland, and ovarian tissues, while perimenopausal women may experience anovulatory menstruation as a result of the deterioration of ovarian function. In addition, there are many other causes of anovulatory menstruation, such as dysmenorrhea, etc. If anovulatory menstruation is suspected, it is necessary to go to the hospital in time to consult the doctor, to clarify the cause of the disease, and then carry out treatment as soon as possible.