Many people have never heard of cytomegalovirus, despite it being a leading preventable cause of non-genetic hearing loss in children
Pregnant women in the UK are often unaware of cytomegalovirus (CMV), despite it being a major cause of permanent hearing loss in babies. The virus is common, often harmless in healthy adults, but when passed from mother to baby during pregnancy, it can lead to serious long-term complications – many of which do not show up at birth.
Congenital CMV affects around 1 in 200 babies worldwide. One in five of these will go on to develop problems such as hearing loss, developmental delays or vision issues. Yet public awareness remains low, and routine screening is currently not offered to expectant mothers or newborns in most parts of the UK.
Hearing loss is one of the most common consequences of congenital CMV. In some cases, it is present at birth. In others, it develops gradually over months or years, even in children who passed their newborn hearing test. This delayed onset can make it difficult for parents to spot the problem early.
“CMV-related hearing loss is a growing issue,” said Eva Opitz, a Clinical Audiologist at Hearology®. “What makes the virus particularly challenging is that it has no symptoms - so all we can do during pregnancy is to be aware of the risk factors and take the appropriate action to minimise the risk. And then, if CMV-related hearing loss does occur, we can make a meaningful difference to the child’s development and quality of life through early diagnosis and the right support.”
No symptoms, but lasting effects
CMV is spread through contact with bodily fluids, particularly the saliva or urine of young children. Pregnant women who work in childcare, healthcare or have toddlers at home are especially at risk. Because most people with CMV show no symptoms, they may not know they’ve been infected.
Simple hygiene measures such as handwashing after changing nappies or wiping a child’s nose can significantly reduce the risk of passing CMV to the developing child. But public health campaigns rarely mention the virus, and many antenatal guides omit it entirely.
In America, a few states have introduced universal screening for newborns, or at least test babies who fail their initial hearing checks. This helps identify babies with congenital CMV early, opening the door to antiviral treatments that may reduce the severity of hearing loss.
In the UK, no such universal policy exists. In fact, routine screening for CMV in pregnancy is not recommended by the UK National Screening Committee. This decision is based on the fact that the majority of babies with CMV develop normally. Furthermore, current screening tests can only identify cases of primary infection and are unable to diagnose secondary infection (either a new strain of CMV or a reactivation of the original strain).
Call for support
Experts say that awareness of CMV must improve among healthcare professionals as well as the general public. Audiologists, speech therapists and paediatricians all have a role to play in identifying affected children and ensuring they receive timely support.
“Because CMV is so common and yet so under-recognised, many parents are caught completely off guard,” Eva added. “We need better public education if we’re going to reduce its long-term impact on families and children.”
CMV is now understood to be a more common cause of hearing loss than conditions such as Down syndrome or foetal alcohol spectrum disorders. Despite this, it continues to fly under the radar in prenatal care.
Further reading
NHS: Cytomegalovirus (CMV) – NHS advice on CMV symptoms, risks and prevention
CMV Action UK – UK charity raising awareness and supporting families affected by CMV
American CDC: CMV and hearing loss – US perspective on how CMV affects a child’s hearing
