Pregnancy and cytomegalovirus (CMV)

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Pregnancy and cytomegalovirus (CMV)
Cytomegalovirus (CMV) is a common viral infection of the herpes family.

The virus causes cold sores and genital sores and is passed on through blood, saliva, breast milk, and other bodily fluids. Between 40-85% of people get infected with CMV at some point in their life, but is it uncommon to experience any symptoms.

Once you have been infected with CMV, you carry the virus in your body, and can pass it on to others. Usually, the virus will only have an effect on people who have problems with their immune system. If you have CMV while you are pregnant, the virus can be passed to the baby through the placenta. The baby can also become infected at birth, or from breastfeeding.

CMV is only harmful to your baby if you catch it for the first time when you are pregnant. On average, there is a 40% chance that the virus will be passed to your baby. About 1 in 10 unborn babies who catch CMV from their mother develop serious problems as a result (about 300 a year).

If you catch the CMV virus early on in your pregnancy, there is an increased risk of miscarriage or damage to the baby, which could result in problems with its hearing or sight. If you get CMV later in pregnancy, it can cause stillbirth or premature labour. there is a chance the baby will be born with congenital CMV and may have jaundice (yellowing of the skin), problems with the liver and blood, or hearing, visual and learning difficulties.

If you have already had the CMV virus and have the antibodies in your body, it is unlikely your baby will be infected. If you come into contact with CMV during pregnancy or you have any symptoms you should visit your GP immediately. If you don't know if you have had CMV in the past you can have a blood test to find out. This is not a routine part of the screening programme during pregnancy because there is no immunisation or simple treatment for it.

Although it is very rare for healthy adults to contract the CMV virus, you should still take precautions such as washing your hands thoroughly, particularly after coming into contact with nappies or the saliva of other children.


A book by Professor Paul Griffiths is now available, which details what he describes as 'The Stealth Virus'.

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