What is CMV?

Cytomegalovirus (CMV) is a common virus that can infect almost anyone. Once infected, your body retains the virus for life. Most people do not know they have CMV, because it rarely causes problems in healthy people. However, if you are pregnant, CMV is cause for concern because the infection can be transmitted to your baby. 

  • 1 in 200 Canadian infants are infected with CMV during pregnancy.
  • 1 in 5 children with congenital CMV will have a permanent disability, such as hearing loss or developmental delay.
  • Young children infected with CMV usually have no symptoms and easily spread the infection to others through saliva and urine.
  • If a pregnant woman is living with a young child infected with CMV, her chance of developing the infection is 1 in 4.

Most babies with congenital CMV appear healthy at birth.

Some babies with congenital CMV who appear healthy at birth can develop signs over time — sometimes not for months or years after birth. The most common of these late-occurring symptoms are hearing loss and developmental delay. A small number of babies may also develop vision problems.

cCMV is the leading cause of non-genetic sensorineural hearing loss and the second leading cause of intellectual disability after Down Syndrome.

Babies with congenital CMV who are sick at birth tend to have significant signs and symptoms, including:

  • Premature birth
  • Low birth weight
  • Yellow skin and eyes (jaundice)
  • Enlarged and poorly functioning liver
  • Purple skin splotches or a rash or both
  • Abnormally small head (microencephaly)
  • Enlarged spleen
  • Pneumonia
  • Seizures