Cytomegalovirus is considered a ubiquitous infection among humans. In the USA approximately 40-60% of mothers are CMV-seropositive, which means that they carry the virus. CMV is spread thru bodily fluids, including breastmilk. Perinatal transmission can also occur during pregnancy, and labor & delivery. Approximately 27% of CMV-seropositive mothers shed the CMV virus in their breastmilk. Term healthy newborn infants are at minimal risk for significant illness from CMV exposure¹, whereas very premature infants born before 30 weeks have a higher risk of significant illness from CMV infection^1,2.

Most neonatal intensive care units in the USA do not screen breastmilk for the presence of the CMV virus. Freezing/thawing of breastmilk helps to diminish transmission of CMV from breastmilk. Pasteurized banked donor milk is free of CMV virus.