Symptomatic congenital CMV infection was originally termed cytomegalic inclusion disease. Only 5% of all congenitally infected infants have severe cytomegalic inclusion disease, another 5% have mild involvement, and 90% are born with subclinical, but still chronic, CMV infection. The characteristic signs and symptoms of clinically manifested infections include intrauterine growth restriction, prematurity, hepatosplenomegaly and jaundice, blueberry muffin–like rash, thrombocytopenia and purpura, and microcephaly and intracranial calcifications. Other neurologic problems include chorioretinitis, sensorineural hearing loss, and mild increases in cerebrospinal fluid protein. Symptomatic newborns are usually easy to identify. The most severe symptomatic congenital infections and those resulting in sequelae are more likely to be caused by primary rather than reactivated infections in pregnant women. Reinfection with a different strain of CMV can lead to symptomatic congenital infection. Asymptomatic congenital CMV infection is likely the leading cause of sensorineural hearing loss, which occurs in approximately 7% of all infants with congenital CMV infection, whether symptomatic at birth or not.
Infections resulting from exposure to CMV in the maternal genital tract at delivery or in breast milk occur despite the presence of maternally derived, passively acquired antibody.