Anemia and the Premature Baby

Ironing out the Details

Anemia is medically defined as a condition in which the body does not have enough healthy red blood cells or a decrease in number of (RBCs) red blood cells. RBCs, also called erythrocytes are shaped like slightly indented, flattened disks and contain the iron rich protein hemoglobin. Blood gets its bright red color when hemoglobin picks up oxygen in the lungs. As the blood travels through the body, the hemoglobin releases oxygen to body cells and tissue.

Anemia is a deficiency in the number of these RBCs.

But what does this really mean? How does anemia affect the premature baby and what can be done to help correct the problem?

Anemia is a common condition and can occur for various reasons. Before birth, a baby’s blood supply carries extra red blood cells in order to help pick up oxygen from the mother’s blood through the placenta. Once a baby is born, and more oxygen is available, they no longer need these extra red blood cells because they begin to breathe on their own. Through this process of change, the body temporarily stops producing the extra red blood cells because there is an excess within the body. The number of RBCs in the blood stream will then slowly decrease. When the level gets too low, the body responds by beginning the production of new red blood cells. This is the normal process for both full term and premature babies. In adults and babies, new blood cells are constantly being made as old ones wear out and are broken down in the body.

This process occurs in cycles. In premature babies, this cycle of red blood cell breakdown is usually faster and red blood cell production is typically slower, therefore a premature baby will become anemic easily.

Preemies may also become anemic from blood loss before or during delivery, a mismatch of the baby’s and mother’s blood types, the need to take frequent blood samples to perform necessary laboratory tests, or an inability to make enough red blood cells to keep up with the preemie baby’s rapid growth rate.

A baby in the NICU is monitored closely with a blood test called Hematocrit and hemoglobin. (Also known as H&H) The hematocrit measures the percentage of liquid blood that is made up red blood cells within the body. Normal hematocrit range is between 35-65 percent. The hemoglobin test measures how much hemoglobin, the oxygen carrying component of red blood cells there is in the blood. The normal hemoglobin range is between 10-17. (Milligrams per deciliter) The numbers do vary greatly depending on the age and the health of the infant. Premature babies will also have a blood test done routinely called a reticulocyte count. (Also known as retic) Reticulocytes are new, immature red blood cells. The presence of reticulocytes in the blood stream is an indication that the body is beginning to produce its own red blood cells.

The body needs iron to make hemoglobin. If there isn’t enough iron available, hemoglobin production is limited, which in turns affects the production of red blood cells. Premature babies are born with lower reserves of iron in their bodies than full term newborns.

As preemies begin to grow, and begin to produce red blood cells again, they quickly run out of the iron that their body has stored. To prevent or help mild anemia, the preemie may be given an iron supplement daily, which is usually in the form of liquid drops.

Most babies become anemic at some point during the NICU stay. Some babies can tolerate low levels of hemoglobin without showing any signs and symptoms. Preemies born at 28 weeks gestation or less, weigh under 1000 grams, who are fighting an infection, or are on a ventilator may not tolerate the low levels of red blood cells and may require a blood transfusion.

A blood transfusion may be indicated if the baby shows increasing signs of anemia. Signs and symptoms can include pale skin color, decrease in activity or too sleepy, tiredness with feeding, increase in breathing (tachypnea), or difficulty in breathing when at rest, a slower than normal weight gain. The baby may also have a high resting heart rate (tachycardia) or may be having more spells of apnea and desaturation.

Transfusions are typically done with a blood product called packed red blood cells. Packed red blood cells contain a high number of RBCs with a lower volume of blood. Blood for transfusion is cross-matched to avoid blood group incompatibility between the donor and the baby. Meaning, the baby’s blood will be drawn and matched up with that of a donor. In some hospitals, it may be possible for the parents of the premature baby to make a direct donation to their infant. The parent and baby must have compatible blood types, and the parent’s blood must be tested, and free of infection. After the blood is collected it takes approximately 72 hours to prepare it for transfusing.

One of the latest treatments of anemia, that is not widely used yet, is the use of erythropoietin. Erythropoietin is a naturally occurring hormone within the body that stimulates the production of new red blood cells. Erythropoietin treatment involves shots, three times a week, and is given with oral iron supplements. Erythropoietin is not yet widely used routinely for the treatment of anemia in the preterm infant.

It is important to remember that anemia is the result of a normal process for all newborn, but is an especially common condition for the premature infant. Anemia is easily treated and is simply one of the many roadblocks that a baby born prematurely will have to face during their NICU journey.

Sources:

Widness JA. Pathophysiology of anemia during the neonatal period, including anemia of prematurity. NeoReviews. 2008; 9:31–e5

Bell EF, Strauss RG, Widness JA, Mahoney LT, Mock DM, Seward VJ, et al. Randomized trial of liberal versus restrictive guidelines for red blood cell transfusions in preterm infants. Pediatrics. 2005;115:1685–1691

Ceriani Cernadas JM. Early versus delayed umbilical cord clamping in preterm infants: RHL commentary (last revised: 7 March 2006). The WHO Reproductive Health Library; Geneva: World Health Organization

Von Kohorn, I. & Ehrenkranz, R. March 2009. Anemia in the preterm infant: Erythropoietin versus erythrocyte transfusion - It's not that simple. Clinical Perinatology. 36(1):111-123.

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