Causes of iron deficiency anemia in children 1. Inadequate intake of iron. Commonly found in children during infancy and adolescence. (1) Infancy. Infants born at full term with normal birth weight may develop mild iron deficiency anemia after 4 months of life, when the iron stored from the mother in the late fetal period is basically used up, if they are still exclusively breastfed and the iron in breast milk is insufficient, at this time, if they do not pay attention to iron intake, they may develop mild iron deficiency anemia in 6~7 months or after 6~7 months. If the infant is premature and fails to look forward after the mother’s pregnancy, he/she will be born with less iron stored in the body and may develop more severe iron deficiency anemia after 6~7 months or 6-7 months if he/she is exclusively breastfed. Therefore full-term, normal birth weight infants, if conditions allow, it is recommended to start adding complementary foods after 4 months of life, paying particular attention to adding iron-rich, iron easily absorbed complementary foods. Premature infants are recommended to start adding iron after 2 months of life. (2) Adolescence. During puberty, children’s body growth increases, and the need for iron increases, so parents do not pay attention to the increase of children’s iron intake, sometimes iron deficiency anemia can occur. However, the common reason for iron deficiency anemia in adolescent children with insufficient iron intake is that children deliberately have reduced dietary intake because they are worried about gaining weight. Another reason is that children have partial diet since childhood, but in adolescence, iron needs increase, at this time still partial diet, resulting in insufficient iron intake. 2 . Excessive loss of iron. Mainly related to disease. Gastrointestinal bleeding is a common cause. Also rare is bleeding from the respiratory tract, which can also cause iron deficiency anemia. Some girls have excessive menstruation and do not pay attention to iron supplementation, which is also one of the causes of iron deficiency anemia.