Congenital CMV Infection
About one out of every 200 infants is born with congenital cytomegalovirus (CMV) infection. Around one in five babies born with congenital CMV infection will have long-term health problems.
A pregnant woman can pass CMV to her fetus following primary infection, reinfection with a different CMV strain, or reactivation of a previous infection during pregnancy. Risk of transmission for primary infection is 30 to 40% in the first and second trimesters, and 40 to 70% in the third trimester. The risk of transmission following non-primary infection is much lower (3%). The risk of complications to the fetus is greatest if a primary infection occurs during the first trimester.
Signs and Symptoms
Most infants with congenital CMV infection never have health problems. About 10% of infants with congenital CMV infection will have health problems that are apparent at birth, which include:
- Jaundice (yellowing of the skin or whites of the eyes)
- Microcephaly (small head)
- Intrauterine growth restriction (low weight)
- Hepatosplenomegaly (enlarged liver and spleen)
- Retinitis (damaged eye retina)
About 40 to 60% of infants born with signs of congenital CMV disease at birth will have long-term health problems, such as:
- Hearing loss
- Vision loss
- Intellectual disability
- Microcephaly (small head)
- Lack of coordination or weakness
Some babies may have hearing loss alone that may or may not be detected by newborn hearing test.
Congenital CMV infection is diagnosed by detection of CMV DNA in the urine, saliva (preferred specimens), or blood, within three weeks after birth. Infection cannot be diagnosed using tests that detect antibodies to CMV. Congenital CMV infection cannot be diagnosed using samples collected more than three weeks after birth because testing after this time cannot distinguish between congenital infection and an infection acquired during or after delivery.
For diagnosis of acquired CMV infection see Interpretation of Laboratory Tests.
For infants with signs of congenital CMV disease at birth, antiviral medications, such as ganciclovir or valganciclovir, may improve hearing and developmental outcomes. Ganciclovir can have serious side effects and has only been studied in infants with symptomatic congenital CMV disease. There is limited information on the effectiveness of ganciclovir or valganciclovir to treat infants with hearing loss alone.
Any infant diagnosed with congenital CMV infection should have regular hearing and vision tests. Most infants with congenital CMV grow up healthy. Early detection and intervention for children with hearing and vision problems may improve outcomes. To learn more, see this CDC website about hearing loss in children.