Iron deficiency anemia refers to a type of anemia caused by a lack of stored iron in the body, which affects the synthesis of hemoglobin. Its characteristics include a lack of stainable iron in organs such as the bone marrow, liver, and spleen, leading to decreased serum iron concentration, decreased transferrin saturation, and decreased serum ferritin. Typical iron deficiency anemia presents as microcytic hypochromic anemia. Therefore, iron deficiency anemia involves a deficiency in iron, a trace element essential for the human body, which is widely present in cells and participates in the body's metabolic processes. The human body has a strict iron metabolism regulatory mechanism to maintain normal physiological levels. Once this homeostasis is disrupted, it can lead to the occurrence of iron deficiency anemia. Factors that affect the distribution, absorption, transport, and storage of iron can all cause iron deficiency anemia.