Diagnosis of CMV infection during pregnancy usually follows an abnormal scan or test. This can be confusing and stressful. However, it does not necessarily mean that the infection has been passed on to your baby or that they will be affected by the virus.
This section aims to explain how doctors diagnose CMV during pregnancy and where you can go for further support.
How do I know if I have CMV?
Most healthy children and adults infected with CMV have no symptoms and may not even know that they have been infected. Others may develop a mild illness; symptoms may include fever, sore throat, rash and fatigue.
Other symptoms, such as swollen glands, liver or spleen, may sometimes be present. However, these can be symptoms of a wide range of conditions, not just CMV.
A blood test can tell if you have an active CMV infection or have had a previous infection. However, if you have had CMV before, it is still possible to catch a different strain. It is therefore important for all pregnant women to follow simple hygiene precautions even if they have had CMV before – nobody is 'immune'.
Why isn’t CMV routinely screened for in pregnancy in the UK?
The UK National Screening Committee has recommended against routine screening for CMV in pregnancy. This is because most babies with CMV develop normally and available tests are not able to distinguish between infections that would seriously affect the baby and those that would not. Neither are there any treatments proven to reduce the risk of the CMV infection passing from the mother to her baby during pregnancy or to reduce the risk of severe problems in babies that have been infected.
Researchers are investigating treatments that could be effective in pregnancy. But for now we need to focus on the simple hygiene measures that can reduce the risk of catching the virus in the first place.
I am pregnant and have been diagnosed with CMV: what does this mean for me and my baby?
Being diagnosed with CMV infection when you are pregnant can be very stressful. However, it does not necessarily mean that your baby has the virus. Of all the women who catch CMV for the first time during pregnancy, only around a third will pass it to their unborn baby.
You may have additional scans or an amniocentesis (taking some water from the sac around the baby) to see if your baby has been infected. It is important to remember that even if the virus has been passed on to your unborn baby, around 4 out of 5 babies born with CMV don’t have any health problems.
Some babies do have more severe symptoms when they are born. Diagnosis in pregnancy can help to ensure that your newborn baby is diagnosed quickly and gets the support that he or she needs.
CMV Action can give you emotional support during this uncertain time. Organisations such as Antenatal Results and Choices (ARC) can also offer professional support to help you through difficult decisions in pregnancy.
Is there any treatment for CMV infection in pregnancy?
Some small-scale studies have investigated a treatment called 'Hyperimmune globulin (HIG)'. This aims to reduce the risk of transmission from mother to baby and to reduce the severity of symptoms in babies that have been infected. However, the amount of evidence available is limited and the effectiveness and risks of this treatment have not been confirmed. A larger-scale study is currently under way.
HIG is therefore not offered in the UK or other countries as routine practice. Some private practitioners in other European countries offer this unproven treatment.