TUESDAY, Sept. 23, 2014 (HealthDay News) -- For babies born at very low birth weights, breast milk is more likely than a blood transfusion to lead to a potentially dangerous infection known as cytomegalovirus (CMV), a new study finds.
The researchers evaluated more than 500 very low birth weight infants -- all of whom weighed 3.3 pounds or less and many who were born to mothers with a history of CMV infection, to see whether breast milk or transfusions carried the bigger risk. Infants born at very low birth weights are especially vulnerable to this viral infection, the study authors noted.
Of 29 babies who developed CMV, none were linked to blood transfusions. But, 27 were linked to breast milk, the study found.
"We didn't know we were going to find so much CMV in breast milk," said study corresponding author Dr. Cassandra Josephson, a professor of pathology and pediatrics at Emory University School of Medicine in Atlanta.
Of the 29 babies who got CMV infections, five developed serious illness and three died. By testing blood, urine and breast milk, the researchers learned that one of the 29 babies developed the infection through the placenta. In another infected baby, the source of infection could not be determined. Infections in the other 27 babies were linked to CMV-positive breast milk.
The study was published Sept. 22 in the journal JAMA Pediatrics.
Just over 300 of the babies in the study needed one or more blood transfusions. A total of more than 2,000 transfusions were given.
Preventive measures were taken before the babies were given blood. The blood was screened for CMV before being given to the infants, and the white blood cells were removed to further reduce the risk of CMV transmission, Josephson explained.
Among all of the mothers in the study, about three-quarters were CMV-positive. CMV is a type of herpes virus. It often has no symptoms, but can lead to infection and serious illness in people with compromised immune systems. CMV can be spread through sexual contact, organ transplants, saliva, urine and respiratory droplets, according to the National Library of Medicine (NLM).
Most people recover in a month or so without medicine, according to the NLM. But, very low birth weight babies can develop serious illness and even die, the researchers noted.
Mothers who know in advance that they may deliver a low birth weight baby can talk to their doctor about preventive measures, Josephson said.
"If they know they are going to deliver early, I would suggest finding out if they are CMV-positive," she said. CMV can be detected through a blood test, according to the NLM.
The study shows that the current standard of care to screen blood is working, said Dr. Deborah Campbell, professor of clinical pediatrics and chief of neonatology at Children's Hospital at Montefiore in New York City.
"It would be helpful for moms to know their CMV status," she said. "Even though CMV can be transmitted to the baby in breast milk, it is still very important for the low birth weight baby if at all possible to receive mother's milk or donor milk."
"Given the benefits of breast-feeding, new strategies to prevent [CMV] are needed, because freezing and thawing breast milk did not completely prevent transmission in the present study," the study authors wrote.
They also noted that the Austrian Society of Pediatrics recommends that premature infants should be fed pasteurized breast milk until they reach 34 weeks of gestational age.
To learn more about CMV infection, visit the U.S. National Institutes of Health.