The causes of heavy menstrual flow are mainly physiological and pathological. Physiological heavy menstrual flow is mainly due to the influence of personal constitution, environmental and dietary factors. For example, excessive intake of cold food during and around the time of menstruation, as well as sudden changes in weather, cold, flu, and excessive fatigue may cause an increase in menstrual flow. Pathological causes of increased menstrual flow are mainly uterine fibroids, adenomyosis, endometrial diseases, most commonly abnormal hyperplasia of the endometrium, and endometrial tumors. If it lasts for a short time, it can be observed temporarily. If it lasts for a long time, you need to seek medical attention because prolonged increased menstrual flow can lead to serious complications.