Cytomegalovirus (CMV) during pregnancy

Cytomegalovirus (CMV) is an infection caused by a common virus in the herpes virus family.

If you’re infected with it during pregnancy, it can be transmitted to your unborn baby. This can cause serious problems, but usually doesn’t and there are ways to reduce the risks.

How can a pregnant woman get CMV?

About half of all Australian pregnant women are thought to have had CMV by the time they get pregnant, and it can stay alive in your body (even if inactive) for many years after you first get infected. Reactivation during pregnancy can occur for women who have had it previously.

The virus is spread from person to person through bodily fluids, including saliva, urine, nasal mucus, breastmilk, vaginal secretions, and semen of infected people. Pregnant women can easily get it particularly if they have other children. It can be transmitted if they’re handling infected children’s toys, nappies, or used tissues.

What are the symptoms of the virus?

Often there are no detectable symptoms, and most people never find out that they’ve been infected. For some, the symptoms are similar to those of glandular fever (which is in the same virus family), such as a fever, cough, cold, or swollen glands.

How can it affect the unborn baby?

You can be tested for CMV infection during pregnancy. It is not routinely recommended, but will be offered to you if you experience viral infection symptoms, or if you are in frequent contact with large numbers of young children (as it’s very common in early childhood).

There is a small risk that it is transmitted to your unborn baby. If they are born with CMV, it is called congenital CMV. They won’t necessarily get sick, but there is the risk of them being born with poor hearing or vision, or an intellectual impairment. Babies born with congenital CMV should have their hearing and vision assessed regularly.

In Australia, out of 1000 live births, about 6 infants will have congenital CMV infection and 1-2 of those 6 will have permanent disabilities of varying degree.

How to avoid getting infected with CMV

Because it seems to be more likely for babies to be born with serious problems if the infection is new during pregnancy, rather than those who have carried the virus in their body for a long time, it is important to practice good hygiene:

  • Regularly and thoroughly wash your hands, particularly after handling dirty nappies and tissues, or after feeding children or handling their dummies. Use gloves if possible.
  • Avoid contact with children’s saliva when kissing them.
  • Don’t share water bottles, cups, or toothbrushes with anyone.
  • Regularly clean surfaces and objects that have come into contact with body fluids.
  • It can be spread through sex too, so if your partner is unwell, it’s a good idea for them to be tested.
  • There is no vaccine to prevent CMV.

Can congenital CMV be treated?

Most babies with congenital CMV are born and grow up with normal health. For pregnant women diagnosed with first-time (primary) CMV infection, they will be referred to a specialist follow up and counselling about the risks and benefits of the treatments available (which are currently experimental).

If you have any concerns at all during pregnancy, speak to your doctor or midwife

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