Prospective cohort study for postnatal cytomegalovirus infection in preterm infants

AIM: Cytomegalovirus (CMV) is a virus that can cause congenital and postnatal infections. Postnatal CMV is mainly transmitted via breast milk and blood transfusions. Frozen-thawed breast milk is used to prevent postnatal CMV infection. A prospective cohort study was conducted to determine the infection rate, risk, and clinical findings of postnatal CMV infection. METHODS: This prospective cohort study included infants born at 32 weeks or earlier than the gestational age (GA). Participants were prospectively screened for infection in the urine by performing urine CMV DNA tests twice, that is, once within the first 3 weeks of life and again after 35 weeks postmenstrual age (PMA). Postnatal CMV infection was defined as a case of CMV negative tests within 3 weeks of birth and CMV positive tests after 35 weeks PMA. CMV-negative blood products were used for transfusions in all cases. RESULTS: A total of 139 patients were subjected to two urine CMV DNA tests. The prevalence of postnatal CMV infection was 5.0%. One patient died of sepsis-like syndrome. The risk factors of postnatal CMV infection were younger GA and older age of the mother. The characteristic clinical findings of postnatal CMV infection were pneumonia. CONCLUSIONS: Frozen-thawed breast milk feeding is not fully effective in preventing postnatal CMV infection. The prevention of postnatal CMV infection is important to further improve the survival rate of preterm infants. Development of guidelines on breast milk feeding for the prevention of postnatal CMV infection is necessary in Japan.