Topics Discussed: anemia; anemia, neonatal; hematology.
Excerpt:"Definition. Anemia developing during the neonatal period (0–28 days of life) in infants of >34 weeks' gestational age is indicated by a central venous hemoglobin <13 g/dL or a capillary hemoglobin <14.5 g/dL.
Incidence. Anemia is the most common hematologic abnormality in the newborn. Specific incidence depends on the cause of the anemia.
Pathophysiology
- Normal physiology. At birth, normal values for the central venous hemoglobin in infants of >34 weeks' gestational age are 14–20 g/dL, with an average value of 17 g/dL. Reticulocyte count in the cord blood of infants ranges from 3–7%. The average mean corpuscular volume of red blood cells (RBCs) is 107 fL. Premature infants have slightly lower hemoglobin and higher mean corpuscular volume and reticulocyte counts. In healthy term infants, hemoglobin values remain unchanged until the third week of life and then decline, reaching a nadir of 11 g/dL at 8–12 weeks. This is known as the "physiologic anemia of infancy." In preterm infants, this decline is more profound, reaching a nadir of 7–9 g/dL at 4–8 weeks. This exaggerated physiologic anemia of prematurity is related to a combination of decreased RBC mass at birth, increased iatrogenic losses from laboratory blood sampling, shorter RBC life span, inadequate erythropoietin production, and rapid body growth. In the absence of..."
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