Checking ferritin during pregnancy is to understand the type of anemia and the degree of iron deficiency, and to help guide the amount of iron supplementation. Iron deficiency anemia may occur during pregnancy due to the increased demand for iron as a result of fetal growth and development; ferritin of 30 or more during pregnancy is considered satisfactory, while 20 or less is considered deficient, and iron supplementation needs to be given under the guidance of a doctor. Iron supplementation is determined according to blood counts, hemoglobin concentration and ferritin values. For example, if you have mild to moderate anemia, normal fetal development, and no discomfort such as fatigue or panic attacks, oral iron supplementation is recommended. If the anemia is severe and accompanied by symptoms such as fatigue, it is necessary to give iron intravenously, or to give a small number of transfusions of red blood cell suspension to correct the anemia and improve the blood supply to the placenta, so as to avoid causing chronic intrauterine hypoxia, intrauterine distress, and intrauterine growth restriction of the fetus.