Primary Prevention of Cytomegalovirus in Pregnancy: Addressing the Gaps (CMV GAP)

Ten children are born every day in the UK with congenital cytomegalovirus (CMV) infection. Over half of infants who have symptoms or signs of CMV at birth have moderate to severe long-term impairments such as hearing loss or neurodisability; of those infants who appear well at birth, nearly 1 in 5 have long-term adverse sequalae. The impact on these families is immense, even for those families whose child has normal hearing and development, as the outcomes are often unpredictable at birth. The cost of CMV in the UK is around £732 million each year.

CMV infection in healthy individuals is often asymptomatic or associated with mild flu-like symptoms and therefore the infection may not be diagnosed in pregnancy. If a woman has a primary CMV infection (i.e. never had CMV infection before, termed 'seronegative'), the risk of transmission to the infant is around 32%; the risk is lower in those women who had had CMV infection previously (CMV IgG antibodies present, termed 'seropositive'), in the order of 1%. Acquisition of CMV infection in the first trimester of pregnancy is associated with the highest risk of adverse outcomes for the infant.

The risk of acquiring CMV in pregnancy can be reduced by making simple adaptions to behaviours to avoid direct contact with saliva and urine of young children - who are the most common transmitters of CMV infection to pregnant women. For example: tasting food first and not eating a young child's left-over food; or kissing on the forehead instead of on the lips; handwashing after nappy changes.

Despite CMV being the most common congenital infection and the leading infectious cause of sensorineural hearing loss and neurodisability, it is much less well known than other conditions that occur at a lower frequency, such as Down's Syndrome.

However, the majority of antenatal care providers do not include information about CMV to women alongside information about how to prevent other, much less common conditions, such as toxoplasmosis. There are currently no national policies that recommend CMV risk reduction measures in pregnancy.