It is not good to have heavy menstrual flow or light menstrual flow, as long as the menstrual flow is within the normal value range is better. Normal menstrual flow is 20-60ml, if the menstrual flow is less than 5ml, it is called as low menstrual flow, if the menstrual flow is more than 80ml, it belongs to excessive menstrual flow, and either low menstrual flow or excessive menstrual flow belongs to abnormal performance. Excessive menstrual flow may be caused by uterine fibroids, abnormal blood clotting function, dysfunctional uterine bleeding, etc. Moreover, prolonged excessive menstrual flow may cause anemia and increase the chances of suffering from gynecological inflammation. Low menstrual flow may be caused by uterine adhesions, polycystic ovary syndrome, endocrine disorders and other reasons. Prolonged low menstrual flow may also cause diseases and may even increase the infertility rate. It is recommended to consult a doctor in time when abnormal menstrual flow occurs. After the doctor’s consultation and relevant examinations, the cause of the disease will be clarified and targeted treatment will be carried out.