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Anemia is a condition in which the blood doesn't have enough red blood cells or hemoglobin or is low in volume. Neonatal anemia is defined as anemia that occurs in an infant who is less than 28 days old. In premature infants, anemia is often present at birth; in healthy term infants, the anemia might not be apparent until a week or two after birth. Several different factors can cause or contribute to the development of neonatal anemia. These causes are categorized into three types: blood loss, red blood cell destruction and insufficient red blood cell production, with the most common cause of anemia in neonates being blood loss.
Blood loss can result from trauma to the placenta or umbilical cord before or during birth or from an internal hemorrhage. In preterm infants, blood loss and anemia are common after blood samples have been taken for laboratory testing. This occurs because a preterm infant has such a small volume of blood that it is reduced significantly after a blood test. Blood loss causing anemia can also result if a large amount blood is transferred from the fetus to the placenta. This can occur if the neonate is positioned above the placenta during or after birth, because gravity causes blood to shift to the placenta.
Red blood cell destruction or insufficient red blood cell production can occur as a result of a hereditary red blood cell disorder. Such disorders include hereditary spherocytosis, which increases the rate of red blood cell destruction, and infection-induced bone marrow suppression, which reduces the rate at which new red blood cells are produced. Insufficient red blood cell production also can result from iron deficiency, but this type of anemia is relatively rare during the neonatal period. Anemia caused by an increased rate of red blood cell destruction can arise from blood group incompatibility between mother and child, from infection or from hereditary blood disorders.
Neonatal anemia can cause a wide range of symptoms, depending on the cause and severity of the anemia. Symptoms can include pale skin, abnormal heart rhythm or pulse, increased requirement for supplemental oxygen, difficulty sleeping, lethargy, low blood pressure and poor feeding. In addition, neonates with anemia are at risk of jaundice, an enlarged spleen and metabolic acidosis, a serious disorder that can be fatal.
Neonatal anemia treatment also depends on cause and severity. A severe case of anemia might require a blood transfusion, and a mild case of transient anemia might not require treatment at all. In the case of preterm infants, anemia can be prevented, or the risks reduced, by limiting the drawing of blood for laboratory tests. When the cause of the neonatal anemia is a hereditary blood disorder, the underlying cause of the anemia also must be treated.