Pregnancy and child

Report warns of threat to unborn babies from CMV virus

"Thousands of pregnant women are unwittingly passing on infections to their unborn babies that cause severe disabilities," is the headline in the Daily Mail after a new report highlighted the risks cytomegalovirus (CMV) can pose to pregnancies.

The paper says cytomegalovirus "can lie dormant in mother's body for years" and "is caught from other children through nappy changing and wiping mouths"

If you are pregnant you can reduce your risk of infection through steps such as frequent hand washing with warm water after coming into contact with any bodily fluids. This includes after a nappy change.

Read more about CMV prevention in pregnancy

What is the basis for this report?

The story was prompted by the release of a report by the charity CMV Action. The charity aims to raise awareness of the virus and campaign for better prevention measures within the health service. They also provide support for those affected by CMV.  

What is CMV?

CMV is a member of the herpes family of viruses. It is a common virus, and is spread through bodily fluids such as saliva and urine.

It can be passed on through close contact with young children, such as when changing nappies. It can also be passed on in other ways that involve contact with bodily fluids, such as kissing or having sex.

CMV doesn't cause symptoms in most people, so many people carrying the virus won't know they have had it. But some people can develop flu-like symptoms such as a fever, sore throat and swollen glands when they are first infected with the virus. 

Up to 80% of adults in the UK are thought to be infected with CMV. Many people are first infected as children. The virus usually remains inactive in the body and does not cause any problems.

It can become a risk if a person infected with CMV has a weakened immune system (someone with cancer or another serious illness), or if a pregnant woman is infected and passes it on to her baby. 

Why is CMV a problem for babies?

A woman can pass an active CMV infection on to her baby in the womb. This only occurs if the woman has an active CMV infection – for example, if she has just been infected for the first time, has just been infected with a different strain, or has an old CMV infection that has reactivated as the result of a weakened immune system.

About 13% of babies infected in this way are estimated to have problems from birth. These can include being born small for their age, having jaundice or a rash, an enlarged spleen and liver, or the lung infection pneumonia.

Some babies also develop more serious problems later on, such as hearing lossvisual impairment or learning disabilities

What does the charity's report say about CMV?

The expert report says CMV is a "neglected public health burden" and calls for more to be done to tackle it. It says:

  • CMV affects almost 1,000 babies a year – more than Down's syndrome, toxoplasmosis or listeriosis
  • one in five babies born with CMV will suffer consequences such as hearing loss, cerebral palsy and epilepsy
  • there is a growing body of evidence that providing pregnant women with this information can reduce the risk of them catching CMV in pregnancy

The report also claims pregnant women receive no advice about CMV in pregnancy. But it is not possible to say to what extent GPs and midwives generally give advice on CMV to women.

It may be the case that the risks of CMV may not be as commonly discussed as those associated with food or alcohol, for example. Advice on CMV in pregnancy has been available on the NHS Choices website for many years.

What can be done now?

The report recommends that:

  • professionals involved in the care of pregnant women improve their understanding of CMV
  • midwives and GPs advise women about reducing the risks of infection
  • health professionals dealing with the foetus and newborns should be alert to the potential signs of CMV infection so more newborns can be diagnosed and treated in the first month of life
  • paediatricians and other professionals working with families should understand the guidelines for managing CMV so more families receive the monitoring and support their child needs
  • there should be more research into developing a vaccine against CMV and treatments that prevent its effects in babies  

What does the report recommend that pregnant women should know?

The report suggests a simple "Don't share, wash with care" four-step approach, which midwives can communicate to childbearing women:

  • Avoid placing objects in your mouth that have been in an infant's mouth previously. So, for example, avoid sharing food, cups and utensils or sucking a child's dummy to clean it after it has been dropped.
  • Avoid kissing young children on the mouth or cheek – they suggest kissing them on the head or giving them a big hug instead.
  • Wash your hands thoroughly with soap and water after coming into contact with any bodily fluids. This includes after a nappy change, or after wiping a toddler's nose or mouth.
  • Thoroughly clean items that have been in contact with bodily fluids.

The charity says that, "Whilst it is hard for busy women to avoid every potential exposure, simply improving hygiene measures can markedly reduce the risk of transmission."

Read more about how to prevent CMV, as well as other infections to avoid during pregnancy.

NHS Attribution