Neutropenia is an abnormally low number of neutrophils in the blood. Neutrophils are a type of white blood cell (leukocyte) that help the body fight infection. A low number of neutrophils create a high risk for infection.

In babies, the most common cause of neutropenia is infection. Neutrophils are produced in the bone marrow and released into the bloodstream to travel to wherever they are needed. Low levels of neutrophils occur when the bone marrow can not replace them as fast as they are being used.

Occasionally, a non-sick infant will have a low neutrophil count for no apparent reason.

A small sample of the baby's blood will be sent to the laboratory for a complete blood count (CBC). A CBC provides much information, such as how many and what types of red cells and white cells are in the blood.

The source of the infection should be identified and treated. In rare cases when the neutrophil count is low enough to be life threatening, the following treatments may be recommended:

• Replacement (tranfusion) of white blood cells using donated blood
• Medicines to stimulate white blood cell production
• Antibodies from donated blood samples (intravenous immune globulin)

The outcome of the baby depends on the underlying cause of the neutropenia. Infection in newborns can certainly be life threatening. A simple blood infection or pneumonia usually does not cause long-term side effects after the neutropenia is successfully treated.