Only 10-15% of neonates with congenital cytomegalovirus infection have symptoms at birth. The most common symptoms are intrauterine growth retardation, microcephaly, petechiae, jaundice, hepatosplenomegaly, intracranial abnormalities, ophthalmological abnormalities and hearing loss. Symptomatic and asymptomatic CMV infections can both have long-term effects. CMV infection during pregnancy is diagnosed using a blood test and possible testing of the amniotic fluid for viral DNA. Infection of the fetus may be prevented by treating the mother with CMV hyperimmune globulin. In the neonate a diagnosis can be made by viral culture or PCR in urine. PCR in saliva could be an alternative. Blood testing is of limited value. If symptoms of CMV infection occur in the neonate, such as petechiae, microcephaly, central nervous system abnormalities, sensorineural hearing loss or chorioretinitis, antiviral treatment should be considered. Long-term follow-up is advisable because of the possibility of delayed-onset hearing loss and chorioretinitis.