Low menstrual flow refers to a menstrual flow of less than 5 ml. Normal menstrual flow is between 20 and 60 ml. There is no such thing as the four major dangers of low menstrual flow, but low menstrual flow may suggest that it is related to infertility, amenorrhea and anemia. 1. Infertility: Low menstrual flow may be due to insufficient estrogen secretion and/or thin endometrium. Chronic thinning of the uterine lining may increase the risk of infertility. 2. Amenorrhea: Low menstrual flow may indicate the presence of hormonal imbalance, which may cause amenorrhea in severe cases. 3. Anemia: Low menstrual flow may indicate the presence of anemia. Women who experience symptoms of low menstrual flow should go to the hospital in time to find out the cause of the problem and treat it under the guidance of the doctor.