Anemia in Premature Babies

Gaps in fetal development can cause severe deficiency

Anemia is simply defined as a lack of red blood cells (hemoglobin). As red blood cells are responsible for transporting oxygen to the cells and tissues of the body, the lack of hemoglobin can lead to lethargy, weakness, breathing problems, heart dysfunction, and other complications.

In premature babies, the complications can be far greater, resulting in developmental problems and a failure to thrive in more severe cases.

symptoms of anemia in premature babies
Illustration by JR Bee, Verywell


It is not uncommon for newborns to have mild anemia. As a rule, the red blood cells of an infant break down faster than new ones are made. Babies tend to be at their most anemic around two to three months and gradually improve over the next two years. Anemia of this type usually doesn't need any treatment other than a healthy diet with plenty of iron.

Preemies are an entirely different story. In some cases, they can develop a more severe type of anemia called anemia of prematurity. This simply means that the preemie hasn't undergone biological changes needed to produce new blood cells independent of their mother.

Some of these changes happen in the final weeks of pregnancy, including the stage when red blood cell production is transferred from the liver to the bone marrow. These gaps in fetal development can easily lead to anemia.

The need to take frequent blood samples to perform necessary laboratory tests during neonatal intensive care can make anemia worse. Even a small blood draw can cause a dramatic drop in the preemie's hemoglobin count.

Symptoms and Diagnosis

The symptoms of anemia can range from subtle to serious based on the underlying cause. A preterm baby with anemia will often experience:

  • Pale color
  • Tachycardia (a rapid heartbeat)
  • Tachypnea (rapid breathing rate)
  • Apnea (interruption of breathing or irregularity of respiration)
  • Bradycardia (slower than normal heart rate)​​
  • Loss of weight and failure to thrive
  • Trouble feeding due to weakness and lethargy
  • An increased need for respiratory support

Anemia is diagnosed by a standard blood test, which measures the number of red blood cells as well as the percentage of red blood cells in a sample of blood (hematocrit). Doctors might also perform a prenatal ultrasound before birth if they see signs of anemia in the fetus.

Treatment and Prevention

Full-term infants don't usually require treatment for anemia. So long as the baby gets enough iron through breast milk or iron-fortified formula or foods, the anemia will typically get better on its own.

In preterm babies, the symptoms of anemia will more often need to be treated. Among the treatment options:

  • Blood transfusion is the fastest way to raise the red blood cell count in a baby. During a transfusion, packed red blood cells from donor blood or a family member (called a direct donation) are delivered through an intravenous (IV) line.
  • Hormone therapy may be provided in the form of recombinant human erythropoietin (rhEPO), a type of glycoprotein which stimulates the production of red blood cells. The advantage of rhEPO is that it can help reduce the number of transfusions a preemie needs, although it takes time to work and can be very expensive.
  • Iron supplements can also be given to infants to help increase their red blood cell counter fast.
  • Delayed cord clamping (roughly 120 to 180 minutes after delivery) has been found to improve iron status and reduce the need for blood transfusion, especially in preterm or underweight babies.
2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Merck Manual. Anemia in the newborn.

  2. Wang M. Iron deficiency and other types of anemia in infants and children. Am Fam Physician. 2016;93(4):270-278.

Additional Reading