Minimal adverse outcomes of postnatal cytomegalovirus infection in term or late preterm infants

Abstract Background: To investigate at what extent breastfeeding and vaginal delivery can increase mother-to-child transmission of cytomegalovirus (CMV) and to observe the clinical outcomes of postnatal CMV infection in infants. Methods: In this secondary study of prospectively collected clinical data and serum samples, April 2012 through March 2015, 380 pregnant women with CMV IgG positive/CMV IgM negative and their 384 infants (4 twin pairs) with gestational age ≥32 weeks were included. CMV IgG and IgM were measured with enzyme-linked immunosorbent assay. Results: Of 384 infants followed up at 10.2 ± 2.3 months age, 177 (46.1%) were defined with CMV infection based on the presence of higher CMV IgG levels than in their mothers. The infection rate in 190 breastfed infants was higher than in 194 formula-fed infants (62.6% vs 29.9%, P < 0.001). Vaginally delivered infants (172) had higher CMV infection rate than 212 infants delivered by caesarean section (55.2% vs. 38.7%, P = 0.001). Compared with formula feeding and caesarean section, breastfeeding and vaginal delivery increased postnatal CMV infection respectively (OR = 3.801, 95% CI 2.474‒5.840, P < 0.001; OR = 1.818, 95% CI 1.182‒2.796, P = 0.007). Nevertheless, CMV-infected infants normally developed and did not show adverse clinical outcomes compared to uninfected infants. Conclusions: Breastfeeding and vaginal delivery can increase postnatal CMV infection; however, the infection does not cause adverse events in term or late preterm infants. Detection of CMV DNA in breastmilk should not be routinely performed, and breastfeeding should be encouraged in these infants.