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Cytomegalovirus (CMV) and Congenital CMV Infection

Cytomegalovirus (CMV) is a common virus that infects people of all ages.  Most people infected with CMV show no signs or symptoms.  However, CMV infection can cause serious health problems for people with weakened immune systems, as well as babies infected with the virus before they are born (congenital CMV).

About CMV

Signs and Symptoms

Most people with CMV infection have no symptoms and aren’t aware that they have been infected. In some cases, infection in healthy people can cause mild illness that may include fever, sore throat, fatigue, and swollen glands.  Occasionally, CMV can cause mononucleosis or hepatitis (liver problem).

People with weakened immune systems who get CMV can have more serious symptoms affecting the eyes, lungs, liver, esophagus, stomach, and intestines. Babies born with CMV can have brain, liver, spleen, lung, and growth problems. Hearing loss is the most common health problem in babies born with congenital CMV infection, which may be detected soon after birth or may develop later in childhood.

Transmission and Prevention

People with CMV may shed (pass) the virus in body fluids, such as urine, saliva, blood, tears, semen, and breast milk. CMV is spread from an infected person in the following ways:

  • From direct contact with urine or saliva, especially from babies and young children
  • Through sexual contact
  • From breast milk
  • Through transplanted organs and blood transfusions
  • From mother to child during pregnancy (congenital CMV)

Regular hand washing, particularly after changing diapers, is a commonly recommended step to decrease the spread of infections, and may reduce exposures to CMV.

Health care providers should follow standard precautions. For more recommendations in healthcare settings, see the Guide to Infection Prevention for Outpatient Settings.

Diagnosis and Treatment

Blood tests can be used to diagnose CMV infections in adults who have symptoms. However, blood is not the best fluid to test newborns with suspected CMV infection. Tests of saliva or urine are preferred for newborns. Healthy people who are infected with CMV usually do not require medical treatment. Medications are available to treat CMV infection in people who have weakened immune systems and babies who show symptoms of congenital CMV infection.

For Pregnant Women

You can pass CMV to your baby. If you are pregnant and have CMV, the virus in your blood can cross through your placenta and infect your developing baby. This is more likely to happen if you have a first-time CMV infection while pregnant but can also happen if you have a subsequent infection during pregnancy.

You are not likely to be tested for CMV. It is not recommended that doctors routinely test pregnant women for CMV infection. This is because laboratory tests cannot predict which developing babies will become infected with CMV or have long-term health problems.

You may be able to reduce your risk. You may be able to lessen your risk of getting CMV by reducing contact with saliva and urine from babies and young children. Some ways do this are:

  • kissing children on the head rather than the lips, and not sharing food or utensils with them
  • washing your hands after changing diapers
  • avoid touching your eyes or the inside of your nose or mouth after coming into contact with the body fluids of an infected person

These steps cannot eliminate your risk of getting CMV, but may lessen your chances of getting it.

Babies Born with CMV (Congenital CMV Infection)

When a baby is born with cytomegalovirus (CMV) infection, it is called congenital CMV infection. About one out of every 200 babies are born with congenital CMV infection. However, only about one in five babies with congenital CMV infection will be sick from the virus or will have long-term health problems.

Women can pass CMV to their baby during pregnancy. The virus in the woman’s blood can cross through the placenta and infect the baby. This can happen when a pregnant woman experiences a first-time infection, a reinfection with a different CMV strain (variety), or a reactivation of a previous infection during pregnancy.

Most babies with congenital CMV infection never show signs or have health problems. However, some babies may have health problems that are apparent at birth or may develop later during infancy or childhood. Although not fully understood, it is possible for CMV to cause the death of a baby during pregnancy (pregnancy loss).

Some babies may have signs of congenital CMV infection at birth. These signs include:

  • Premature birth
  • Liver, lung and spleen problems
  • Small size at birth
  • Small head size
  • Seizures

Some babies with signs of congenital CMV infection at birth may have long-term health problems, such as hearing loss, vision loss, intellectual disability, small head size, lack of coordination, weakness or problems using muscles, and seizures.  Some babies without signs of congenital CMV infection at birth may have hearing loss. Hearing loss may be present at birth or may develop later in babies who passed their newborn hearing test.

Congenital CMV infection can be diagnosed by testing a newborn baby’s saliva, urine, or blood. Such specimens must be collected for testing within two to three weeks after the baby is born in order to confirm a diagnosis of congenital CMV infection.

Medicines, called antivirals, may decrease the risk of health problems and hearing loss in some infected babies who show signs of congenital CMV infection at birth.  Use of antivirals for treating babies with congenital CMV infection who have no signs at birth is not currently recommended.  Babies with congenital CMV infection, with or without signs at birth, should have regular hearing checks.  Regularly follow-up with your baby’s doctor to discuss the care and additional services your child may need.