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Cytomegalovirus (CMV) during pregnancy

Key facts

  • Cytomegalovirus (CMV) is a common virus that usually does not cause any symptoms, but can be dangerous for your baby if you catch it during pregnancy.
  • CMV is spread through body fluids — it can appear in urine and saliva for years after you have been infected.
  • People who have young children or work in child care centres are at higher risk of catching CMV.
  • Most unborn babies who are infected with CMV will not have any problems, but a small number will have poor hearing and vision, developmental delays or intellectual disability.
  • CMV cannot be prevented, but the best way to reduce your risk is with good hygiene.

What is cytomegalovirus (CMV)?

Cytomegalovirus (CMV) is a common virus that usually does not cause any obvious symptoms. You may not know you are infected. About half of the adult population in Australia have had CMV.

After you catch CMV, the virus stays in your body in an inactive form — this means that you do not experience symptoms. It can become active again when your immune system (Opens in new tab) is weaker than usual, such as during pregnancy.

CMV can pass to your unborn baby, especially if you are infected for the first time during pregnancy. This may lead to serious problems for your baby.

How does CMV spread?

CMV spreads from person to person through contact with body fluids, such as:

It can also spread through coughing and sneezing, or by touching objects that have infected body fluids on them. 

You can get CMV from having sex, a blood transfusion (Opens in new tab) or an organ transplant (Opens in new tab). 

Babies can become infected with CMV through breast milk if the virus is in the milk. 

If your child has had CMV, the virus can continue to appear in their urine and saliva for years afterwards. It can infect other people who have not had CMV, for example, by having contact with the child's toys, used tissues or nappies.

Congenital CMV

If you have CMV when you are pregnant, the virus can travel across the placenta and infect your baby. This is called congenital (present from birth) CMV.

Your baby can get congenital CMV if:

  • it is the first time you've been infected with CMV (known as primary infection)
  • you have had CMV before and the virus in your body becomes active again (known as reactivation)
  • you get infected with a different strain (type) of CMV 

You are more likely to pass the virus on to your baby if you have a primary CMV infection during pregnancy. CMV can spread to your baby at any stage of pregnancy, but the risk is higher in the first half.

What are the risk factors for CMV in pregnancy?

People with young children at home and people who work in child care centres are at higher risk of catching CMV if they have not had it before.

What are the symptoms of CMV?

CMV usually does not cause noticeable symptoms. In some people, it may cause mild symptoms such as:

These symptoms usually go away by themselves.

CMV can cause serious illness in people with a weak immune system (Opens in new tab), for example people with HIV (Opens in new tab) or people having chemotherapy (Opens in new tab) for cancer treatment.

Most people do not know they have a CMV infection, or if they have had it before. You might find out from a blood test that you have had it.

How does CMV affect my baby?

Most babies born with CMV do not have symptoms or health problems as a result of the virus. Your baby is more likely to be affected if you get CMV for the first time during pregnancy. Your doctor may see signs of congenital CMV on a pregnancy ultrasound.

A baby born with congenital CMV may have symptoms such as:

Congenital CMV also increases the risk of miscarriage, stillbirth or death before 3 months of age. It can also increase your baby’s risk of poor growth.

If your baby is born without symptoms, they may develop health problems later. These may include:

Babies who are born without any obvious symptoms or hearing loss have a lower chance of developing problems later.

If your baby has abnormal hearing test results, your doctor should recommend testing for CMV.

How common is CMV in pregnancy?

Most adult females have been exposed to CMV before pregnancy, meaning primary infection is less common. 

How is CMV diagnosed in pregnancy?

There is a blood test to check for CMV. In Australia, it’s not part of standard testing in pregnancy. CMV testing in pregnancy is recommended for people who:

  • develop symptoms of a viral infection that suggests CMV
  • have frequent contact with young children (such as healthcare or child care workers)
  • know they have been exposed to someone with a new CMV infection
  • have had a pregnancy ultrasound that shows signs of congenital CMV

Ask your doctor if they recommend testing for CMV. 

If your test result shows you have CMV, your doctor may recommend other tests to see if your baby has CMV too. Most unborn babies who test positive for CMV during pregnancy will not have long-term complications.

If you have CMV during pregnancy, your baby should be tested for CMV after birth.

Speak with your doctor if you have any questions or concerns about CMV or testing.

How is CMV treated during pregnancy?

There is currently no treatment that clearly lowers the risk of your unborn baby getting CMV during pregnancy. 

If your baby tests positive for CMV, your doctor may recommend regular hearing tests and eye checks to identify any issues early.

Can CMV be prevented?

There is no vaccine to prevent CMV infection. The best way to reduce your chance of infection with CMV is with good hygiene habits.  

Try to lower your chance of contact with body fluids that may be contaminated with CMV. If you are pregnant:

  • wash your hands regularly and thoroughly with soap and water, especially when feeding and caring for children, changing nappies, wiping noses or handling anything with body fluids
  • clean all surfaces and objects that may have body fluids on them
  • wear gloves when changing nappies
  • avoid kissing children on the lips or putting dummies in your mouth
  • avoid sharing food, cups, utensils or toothbrushes

If you have any concerns, discuss them with your doctor or midwife.

Resources and support

For more information about CMV transmission and symptoms, as well as congenital CMV, see the Sydney Children's Hospitals Network (Opens in new tab) website.

For more information about CMV in pregnancy including prevention, symptoms, diagnosis and management, see the NSW Health website (Opens in new tab).

Information for Aboriginal and/or Torres Strait Islander peoples

Read more on CMV in pregnancy for Aboriginal and/or Torres Strait Islander peoples (Opens in new tab), with simple steps to reduce CMV risk.

Watch the No Germs on Me (Opens in new tab) video on hand washing.

Speak to a maternal child health nurse

Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 (Opens in new tab) or video call. Available 7am to midnight (AET), 7 days a week.

Last reviewed: March 2026

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Cytomegalovirus (CMV) infection fact sheet | NHMRC

How it spreadsCMV infection spreads through contact with body fluids such as urine, saliva, blood or breastmilk. It can spread from person to person through close contact, such as sharing eating utensils, or through contact with contaminated objects such as toys or nappies. People can be infectious for months to years after their initial infection, because they can keep shedding the virus in their urine or saliva. Exclusion periodNot excluded - people with CMV can attend the service.
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Learn more on NHMRC website