Preterm infants are at risk of acquiring human cytomegalovirus (CMV) infection through breast milk transmission, possibly leading to serious symptoms, as suggested by previous studies. Over a period of 8.5 years, we compared infants infected postnatally with CMV with noninfected controls to determine whether CMV infection transmitted through breast milk poses serious acute risks.

CMV monitoring included maternal serologic testing and biweekly viral culture and polymerase chain reaction in breast milk and infant urine. Clinical and laboratory test findings were assessed retrospectively in infected infants and controls matched for gestational age during the initial hospital stay.

Forty CMV-infected infants met the study criteria. They had lower minimal platelet and neutrophil counts and a higher frequency of C-reactive protein (CRP) elevations to 10 to 20 mg/L than their matched controls (P ≤ .001). But no association of CMV infection with bronchopulmonary dysplasia, necrotizing enterocolitis, growth, or CRP elevations to > 20 mg/L was found. Cholestasis appeared in 3 infants in the CMV-infected group, but disappeared within 10 weeks.

Neonatal symptoms related to postnatal CMV infection were transient and had no affect on neonatal outcome in these infants, in contrast with uncontrolled reports. Whether withholding or pasteurizing breast milk is warranted, however, depends on long-term outcome.