Studies say most pregnant women have never heard of a virus now considered the leading non-genetic cause of disability in newborns.

Cytomegalovirus (CMV) causes hearing loss, vision loss and intellectual disability, but it is relatively simple to prevent.

A new study from the University of New South Wales says CMV is now the leading non-genetic cause of disability in newborns, but a recent Swiss study found most pregnant women had never heard of it.

About half the population has been infected with CMV by the time they reach adulthood, while over seventy-five per cent of people have had it by the age of 40.

After someone is infected, the virus can lay dormant, showing no symptoms until the person has a weakened immune system.

It is a different story for pregnant women, who tend to be asymptomatic themselves, but can transmit the disease to the foetus if they contract it for the first time in pregnancy.

About 30 per cent of women with CMV will pass it on to their babies, causing lasting problems in about 10 per cent og infected babies.

Issues include deafness, poor eyesight and intellectual disability.

Pregnant women are not routinely screened for CMV disease and there is currently no treatment for it during pregnancy, but it is in fact easily prevented.

CMV is typically transmitted via contact with infected secretion,including saliva, urine and stool or faeces.

The CMV Association of Australia says the most important thing for pregnant women is simple hand-washing.

The group’s website also features a range of resources for new parents to avoid the potentially harmful yet largely unknown condition.