Anemia can lead to reduced menstrual flow and even amenorrhea. Anemia can affect all organs of the body, including the uterus and ovaries. If the anemia is mild, with a hematocrit of 10g or more, the effect on menstruation is less obvious. In moderate or severe anemia, it will lead to the poor state of all organs of the body and weaken the oxygen supply, which will also have an effect on ovarian function, and the patient’s ovulation will be affected. If the patient does not ovulate, it will lead to no menstruation. If the patient has severe anemia, menstrual disorders and amenorrhea may occur. When the state of the whole body, oxygen supply is weakened and there is severe anemia, the endometrium is poorly developed and when it is shed naturally, the endometrium is relatively thin, so it is shed less, accompanied by less blood-containing components, leading to a decrease in menstrual flow.