Anemia of Prematurity

Anemia is a condition in which the concentration of red blood cells or hemoglobin in the blood is below normal. Hemoglobin is a substance in red blood cells that carries oxygen to the tissues in the body. Anemia results in not enough oxygen reaching these tissues.

Most babies develop a normal anemia called physiologic anemia, with the lowest levels occurring around 10–12 weeks. Physiologic anemia is usually mild but it can be more severe and occur earlier (lowest levels 4-6 weeks) in babies born prematurely. This is because:

  • Iron transfers from the mother to the baby in the third trimester of pregnancy. Premature infants may be born before they receive sufficient iron from their mothers.

  • Red blood cells in premature babies wear out more quickly.  

  • Premature babies lose blood due to numerous blood tests taken to monitor problems related to prematurity.  

  • Premature babies do not make blood cells as efficiently as full-term babies.  


Physiologic anemia develops because red blood cells wear out after a period of time. The body normally starts making red blood cells at 6 –8 weeks after birth. Until then the red cells that are lost are not replaced.


If the anemia is very mild, there may be no symptoms. The most common symptoms of anemia in premature babies include:

  • Poor weight gain.  

  • Difficulty feeding.  

  • Pale skin.  

  • Rapid heart rate.  

  • Decreased activity.  

  • Breathing stops for periods of time (apnea).


Your baby will have blood tests that measure the concentration of red blood cells. Other tests may be run to rule out possible causes of anemia and to check to see if the baby's body is making new red blood cells.


Treatment depends on how premature your baby is, the severity of the anemia, your baby's symptoms, and your baby's overall condition. Treatment may involve:

  • Limiting the number of blood tests your baby receives. This prevents the anemia from getting worse.  

  • Diet supplements of specific vitamins and iron.  

  • Red blood cell transfusions.  

  • Medicines.  

  • Feeding the baby an iron-enriched formula.


  • Give your baby vitamins and iron supplements as prescribed by your baby's health care provider.  

  • Give your baby medicines as directed by your baby's health care provider.  

  • Follow through with blood tests and office visits as recommended by your baby's health care provider.  


Your baby has signs that the anemia may be returning. Watch for:

  • Pale skin.  

  • Easy tiring.  

  • Poor feeding.  

  • Excessive sleepiness.  


  • Your baby's breathing is very fast or labored.

  • Your baby has pauses in breathing (apnea) that last more than 20 seconds.