There are many possible causes of anemia in premature infants. The anemia of prematurity is a "physiologic" anemia related to a transient defect in detecting and responding to hypoxia.


Features of anemia of prematurity:

(1) premature infant

(2) presence of anemia with hypoxemia

(3) low serum erythropoietin levels

(4) reticulocytosis following administration of erythropoietin and iron



• Iron needs to be administered with the erythropoietin for an optimum response.


Factors contributing to the anemia:

(1) In premature infants oxygen sensing is done in hepatocytes, which are relatively insensitive to hypoxia. In full-term infants oxygen sensing is done in the kidney. There is less secretion of erythropoietin for a degree of anemia.

(2) rapid rate of growth

(3) phlebotomy for laboratory testing

(4) lower hemoglobin in fetus (normal range in cord blood of full-term infant is 13.5 to 20.5).


Although administration of erythropoietin and iron will increase reticulocytosis, it may not reduce the need for blood transfusion or impact clinical outcome.


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