An otherwise healthy 3-month-old infant with a birth hemoglobin of 19 mg/dL has preoperative hemoglobin of 10 mg/dL. The most likely explanation for this anemia is?

An otherwise healthy 3-month-old infant with a birth hemoglobin of 19 mg/dL has preoperative hemoglobin of 10 mg/dL. The most likely explanation for this anemia is?

• A. Sickle cell trait
• B. Sickle-cell anemia
• C. Iron deficiency
• D. It is a normal finding

Answer: (D)

Physiologic anemia of infancy is a normal, temporary drop in hemoglobin that occurs in healthy term infants during the first few months of life. At birth, Hb is high because of fetal hemoglobin and the rapid red cell mass. After birth, the infant’s plasma volume expands and erythropoietin production falls as oxygen needs stabilize, while red cells have a shorter lifespan. The net effect is a fall in hemoglobin to about 9–11 g/dL by around 2–3 months of age. In this healthy 3‑month‑old, a preoperative hemoglobin of about 10 g/dL fits this expected pattern, so it is considered a normal finding rather than a pathologic cause of anemia. Sickle cell trait or disease would not typically present as a simple, physiologic drop to 10 g/dL in an otherwise well infant and would usually show other clinical or hematologic features. Iron deficiency could cause anemia, but in a healthy infant with a normal birth hemoglobin and no growth or feeding concerns, iron deficiency is less likely this early, and it would usually present with different blood indices and a more gradual decline.

Physiologic anemia of infancy is a normal, temporary drop in hemoglobin that occurs in healthy term infants during the first few months of life. At birth, Hb is high because of fetal hemoglobin and the rapid red cell mass. After birth, the infant’s plasma volume expands and erythropoietin production falls as oxygen needs stabilize, while red cells have a shorter lifespan. The net effect is a fall in hemoglobin to about 9–11 g/dL by around 2–3 months of age. In this healthy 3‑month‑old, a preoperative hemoglobin of about 10 g/dL fits this expected pattern, so it is considered a normal finding rather than a pathologic cause of anemia.

Sickle cell trait or disease would not typically present as a simple, physiologic drop to 10 g/dL in an otherwise well infant and would usually show other clinical or hematologic features. Iron deficiency could cause anemia, but in a healthy infant with a normal birth hemoglobin and no growth or feeding concerns, iron deficiency is less likely this early, and it would usually present with different blood indices and a more gradual decline.