While you might know all about other conditions in pregnancy and for babies, CMV is one that is far less well known. Here’s why you should be aware of it…
CMV, or cytomegalovirus, is a common virus that can affect you whatever age you are. It is related to the herpes virus that causes cold sores and chicken pox (NHS, 2000).
If you have CMV, it’s likely you won’t have any signs or symptoms or any long-term effects. It stays in the body and your immune system usually controls it. Yet it can cause serious health problems to unborn babies if passed to them when it is active. It does not cause problems to babies who pick it up during or after the birth (CMV Action, 2018).
CMV is active:
- when it first infects someone
- if it is reactivated due to a weakened immune system
- or if someone is re-infected with a different strain of CMV. (NHS, 2020)
Pregnant women can pass an 'active' CMV infection on to their unborn baby. This is known as congenital CMV (NHS, 2020).
"About one third of women who get CMV for the first time while they’re pregnant will pass the virus to their unborn babies (Kenneson et al, 2007)."
CMV: how common is it?
Around 3 in 1,000 babies are born with CMV in the UK (Townsend et al, 2011).
CMV: what are the symptoms in children?
Most babies born with CMV won’t have any symptoms and will not experience any complications (Townsend, 2011). Around 1 in 10 of those with the infection will show symptoms, and most of these will experience long-term complications (Townsend, 2011).
In an unborn baby, the signs of congenital CMV infection are:
- small growth rates
- small head size (microcephaly).
(Goderis et al, 2013; CDC, 2020)
When the baby is born, if they show symptoms, they might include:
- little red spots (petechiae)
- enlarged liver and spleen
- calcium deposits in the brain
- developmental or learning difficulties
- hearing loss.
(Goderis et al, 2013; CDC, 2020)
Congenital CMV is responsible for around 25% of childhood hearing loss (Manicklal et al, 2013).
Some children with congenital CMV go on to develop:
- autism visual impairment
- cerebral palsy
(CDC, 2020; CMV Action, 2018)
CMV diagnosis in children
You can confirm whether a newborn has the CMV virus with a saliva, urine or blood test (CMV Action, 2018).
The test is done in the first three weeks of a baby’s life to make sure that it is a congenital CMV infection (CMV Action, 2018). If they picked up CMV during or after birth, it won’t cause any long-term problems (CMV Action, 2018).
CMV: what are the symptoms in adults?
If you have CMV, it’s likely you won’t know you have it but you might get symptoms in the form of:
- a fever
- a sore throat
- swollen glands.
It’s not easy to diagnose but if you do develop the above flu-type symptoms when you’re pregnant, speak to your GP and ask them to check for CMV.
CMV diagnosis in adults
Most CMV infections aren’t diagnosed because there are few or no symptoms. A blood test can show if you have it or have had it previously though.
If you have had it, bear in mind that it is possible to get it again (NHS, 2020).
CMV is spread mainly through close contact with someone who already has CMV. The virus can be found in bodily fluids, including urine, saliva, blood, mucus and tears (NHS, 2020).
It’s really common for small kids – especially those who go to nursery or playschool – to catch CMV (Cannon et al, 2014).
The main way a pregnant woman catches CMV is from the saliva and urine of young children (Cannon and Davis, 2005). This means pregnant women who have young children or work with young children should be especially careful (Cannon and Davis, 2005; Joseph et al, 2006).
At the moment, there’s no vaccine against CMV, and no treatment for pregnant adults (NHS, 2017). So ways to protect yourself include:
- Washing hands using soap and water after changing nappies, wiping noses, feeding etc.
- Washing toys or other things that get children’s saliva or urine on them.
- Not sharing cups, cutlery etc. with your young children.
- Avoiding kissing babies, toddlers and small children directly on the mouth. Kiss them on the forehead or cheek instead.
(Stowell et al, 2013; NHS 2020)
Newborns with symptoms can be treated with antiviral medications (NHS, 2020).
Hearing loss from CMV is managed with hearing aids and cochlear implants.
After that, all babies born with CMV will be monitored regularly. They’ll have a full range of tests after CMV has been diagnosed, which will include:
- blood count, platelet count and liver function tests
- brain scan
- hearing test
- eye test.
Their growth and development will be regularly monitored too.
What about breastfeeding?
Children born at full term to women with known active CMV infection can be breastfed. CMV can be passed from a mother to her child through breast milk, but in full-term babies the virus is harmless as your baby's immune system is strong enough to deal with it. The milk also contains antibodies that are protective against CMV (Bryant et al, 2007).
The immune system of premature babies may not be strong enough to deal with a CMV infection, so discuss with health professionals the best way to feed your baby if they are born prematurely (Bryant et al, 2002).
CMV and ethnicity
American research has found rates of CMV to be higher in Black, Hispanic and Asian groups without a difference in severity of symptoms (Fowler et al, 2018; Dowd et al, 2008). However, further research has linked increased rates of CMV to social disadvantage suggesting that it is social demographic factors and close community living, rather than race, which impacts rates of infection (Lantos et al, 2017).
This page was last reviewed in March 2021.
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(2013) Hearing loss and congenital CMV infection: a systematic review. Pediatrics. (5):972-982. Available from: https://www.ncbi.nlm.nih.gov/pubmed/25349318 [Accessed 28 March 2021]
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Iwasenko JM, Howard J, Arbuckle S, Graf N, Hall B, Craig ME, Rawlinson WD. (2011) Human cytomegalovirus infection is detected frequently in stillbirths and is associated with fetal thrombotic vasculopathy. J Infect Dis. 203(11):1526-1533. Available from: https://academic.oup.com/jid/article/203/11/1526/862620 [Accessed 28 March 2021]
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