About 15% of babies with congenital CMV will not have signs at birth but will later develop hearing loss. Posted bymicrogen@dev May 3, 2024May 3, 2024 Leave a comment on About 15% of babies with congenital CMV will not have signs at birth but will later develop hearing loss. About 15% of babies with congenital CMV will not have signs at birth but will later develop hearing loss.