Some Breast Milk Could Kill Preemie Babies—Better Ask the Neighbor for a Glass

While maternal breast milk has proven an effective way of passing vital nutrients and immune-boosting proteins into a newborn baby's system, a new study published in journal JAMA Pediatrics suggests that it may leave premature infants particularly vulnerable to cytomegalovirus (CMV) infection. In most cases causing serious disease, and in chronic infections, may even lead to death.

As a member of the viral family commonly known as Herpesviridae, cytomegalovirus is related to common infections like chickenpox and the herpes simplex. Although, like its family members, CMV is a life-long infection once exposure has taken place, the virus is rarely lethal except under extreme conditions. However, in infants born with low birth weights and individuals whose immune systems have been compromised, the virus can have serious side effects that may even lead to death.

In the new study conducted by researchers at Emory University in Atlanta, a clinical study enrolled 462 mothers and 539 infants born with very low birth weights in three neonatal ICUs between January 2010 and June 2013.

Over the course of the babies' first 90 days of existence, with the exception of those who developed severe disease or died during the study, 2,061 blood transfusions were administered to 310 (57.5 percent) of the infants and all tested negative for CMV infection. However, 29 of the infants, five of whom died before the end of the study, were found to acquire a CMV infection from being fed breast milk by their CMV-positive mothers.

"We believe our study is the largest evaluation of both blood transfusion and breast-milk sources of postnatal CMV infection in very low birth weight infants" lead author Dr. Cassandra Josephson says.

And though the research indicated a smaller number within the test-subject population, the researchers estimate that between 10 and 20 percent of all very low birth weight infants who are fed  CMV positive breast milk will develop severe forms of the infection.

"Previously, the risk of CMV infection from blood transfusion of seronegative or leukoreduced transfusions was estimated to be 1 to 3 percent" Josephson says. "But we showed that using blood components that are both CMV-seronegative and leukoreduced, we can effectively prevent the transfusion-transmission of CMV. Therefore, we believe that this is the safest approach to reduce the risk of CMV infection when giving transfusions to very low birth weight infants."

The researchers, in collaboration with the American Academy of Pediatrics, recommend that mothers and infants should go through routine screening for CMV infection to best address possible issues and that CMV-positive mothers should pasteurize breast milk, until their preemies are of the correct gestational age of 34 weeks.