The common causes of menstrual blood reflux during menstruation are abdominal cold, eating too cold food, uterine malformation, etc., as follows: 1. If you do not pay attention to abdominal warmth during menstruation, when the abdomen is cold, the blood vessels in the endometrial area contract, so there will be a reduction in the amount of menstrual blood. 2. If women eat ice cream, cold drinks, food taken out of the refrigerator during menstruation, etc., stimulate the pelvic floor tissue and uterus 3. If the uterus is congenitally dysplastic, the menstrual blood of the uterus cannot be discharged smoothly, and menstrual blood accumulates in the uterine cavity, the discharge of menstrual blood is obstructed, and the pressure in the uterine cavity will rise, leading to the appearance of menstrual blood reflux. In order to avoid menstrual reflux during menstruation, it is recommended to keep the abdomen warm to avoid getting cold and avoid eating spicy, stimulating and cold food to avoid affecting normal menstruation.