Menstruation is formed by the shedding of the endometrium and it is influenced by hormonal changes in the body. If there is a normal pattern of hormonal changes in the body, the menstrual cycle is also normal, otherwise menstrual irregularities will occur. The main hazards are as follows: 1. Infertility: Irregular menstruation is one of the main causes of infertility, which can lead to non-ovulation, so women who have plans to have children should do a good job in regulating their menstruation. 2. Anemia: Non-ovulation may lead to thickening of the endometrium, excessive menstruation when menstruating, sometimes dripping, prone to anemia, often manifesting as weakness, dizziness and other symptoms, endangering health. 3. 3.It may lead to gynecological diseases; irregular menstruation may cause fibroids, breast diseases, endometrial polyps, etc. 4.Long-term menopause and amenorrhea may cause the endometrium to be affected by the long-term effect of estrogen, which may lead to the risk of endometrial cancer.