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Cytomegalovirus (CMV)

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What is CMV?

CMV is a common virus in the United States. After the initial infection, the virus is inactive at times, but it is a life-time infection. CMV is the most common congenital (present at birth) viral infection. 

How is CMV spread?

CMV without symptoms is common in older babies and young children. It is found in saliva, urine, semen, and other body fluids. The virus is easily spread in households and in daycare centers. It can be transmitted to the fetus during pregnancy and to the baby during delivery or in breast milk.

What is congenital CMV?

When a baby has CMV before birth, it is called congenital CMV. Most babies with congenital CMV never have any health problems or show signs of infection. However, some babies with congenital CMV will have signs of the infection at birth, or that develop later.

Unlike congenital CMV, transmission of CMV at time of delivery or through breast milk does not typically cause illness in the baby.

Why is congenital CMV a concern?

Most babies with congenital CMV never have any health problems. However, some babies with congenital CMV will have serious complications including hearing loss, vision loss, developmental or motor delays, or seizures.

What are the signs of congenital CMV?

Most babies with congenital CMV will not have symptoms of the infection at birth, and symptoms will differ for each baby. Symptoms may include:

  • Premature birth
  • Low birthweight
  • Small head (microcephaly)
  • Liver enlargement and yellowing of the skin and white of the eyes
  • Blueberry muffin rash
  • Hearing loss

How is congenital CMV diagnosed?

Most infections with CMV in the mother are not diagnosed because the virus produces few symptoms. A mother who has had CMV infection in the past may have antibodies present in her blood. Babies with congenital CMV may have testing done on their throat, blood, or urine. CMV screening at birth may also be part of the routine newborn screen in your state, however, this will need to be confirmed with additional testing.

How is congenital CMV treated?

Treatment for CMV should be started within the first month of life to provide a possible benefit in improving hearing or neurologic problems.  Not all infants with congenital CMV require treatment. Specific treatment recommendations for cytomegalovirus will be determined by your baby's provider based on:

  • Your baby's gestational age
  • Your baby’s symptoms
  • Your baby's tolerance for specific medications
  • Expectations for the course of the disease

If your provider decides to pursue treatment, blood draws may be collected to monitor safety of the treatment course.

Your provider team may also recommend additional testing such as:

  • Hearing tests by an audiologist
  • Eye exam by an ophthalmologist
  • Head ultrasound
  • Developmental checks

How can I prevent the spread of CMV?

You may be able to lessen your risk of getting CMV by reducing contact with saliva and urine from babies and young children. These precautions are especially important for pregnant people. The saliva and urine of children with CMV have high amounts of the virus. You can avoid getting a child’s saliva in your mouth by, for example, not sharing food, utensils, or cups with a child.  Proper hand-washing with soap and water for at least 15 seconds is effective in removing the virus from the hands, and you should always wash your hands after changing diapers.  

What else do I need to know?

Can my child go to daycare? Yes. Your child does not need to be treated differently from other children. Daycare providers should follow routine practices and wash their hands after changing diapers.

Can I breastfeed? Yes. It is safe to breastfeed your child with congenital CMV.


This information is not specific to your child but provides general information. If you have any questions, please call your clinic.

Reviewed 8/2022

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This page is not specific to your child, but provides general information on the topic above. If you have any questions, please call your clinic. For more reading material about this and other health topics, please call or visit Children's Minnesota Family Resource Center library, or visit

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