The common but deadly virus most pregnant women have never heard of

All pregnant women should be warned about a herpes-like virus and taught how to protect their babies from its potentially deadly and debilitating complications, according to long-awaited changes to national guidelines.

Congenital cytomegalovirus (CMV) is the most common cause of congenital infection, and the leading infectious cause of disability in babies, but very few pregnant women or women trying to conceive have heard of it.

Almost 2000 babies in Australia are born with congenital CMV every year, and roughly 400 children will develop physical or intellectual disabilities caused by the infection, including deafness, blindness, cerebral palsy, microcephaly and epilepsy.

The virus – transmitted through bodily fluids such as saliva, tears, urine and breast milk – can severely affect the placenta and fetal organs, potentially leading to stillbirth, neonatal death and the severe condition cytomegalic inclusion disease.

A crucial update to the federal government’s Australian Pregnancy Care Guidelines recommends that all women be informed by their maternity team about CMV and the hygiene strategies to reduce the risk of infection.

The update also recommends that women at higher risk – including those with young children or who work with children – are offered a blood test to detect CMV early in pregnancy.

CMV is 20 times more common than toxoplasmosis and listeria during pregnancy.

But Professor Nadia Badawi, neonatologist and Cerebral Palsy Alliance chair of research, said less than 20 per cent of pregnant women are aware of CMV and how to reduce their risk of infection, and just 10 per cent of maternal health professionals routinely discuss CMV with pregnant patients.

“It’s really shocking when we know that practising safe hygiene precautions reduces the risk of catching CMV in pregnancy by 70 per cent [from 7 per cent to 1.5 per cent] in high-risk women – those with toddlers and those working in childcare,” Badawi said.

Jennifer Kennedy had been trying for another baby when her son brought home a daycare bug in October 2023.

“We just thought it was a horrible cold. We had never heard of CMV.”

Days later she discovered she was pregnant. But, from her 20-week scan, her unborn son Harry displayed abnormalities. A blood test confirmed she had CMV levels so high that she must have contracted the virus during her pregnancy.

Harry was among the small percentage of babies so severely affected by CMV that he was unlikely to survive the pregnancy or neonatal period.

“We made the decision to terminate the pregnancy, which is something I had always said I would never do, as a Christian,” Kennedy said. “It was the most incredibly difficult decision we have ever made or will ever make.

“If I had known about CMV, as soon as I realised I was pregnant I would have gone to get a blood test and could have been referred for antivirals,” she said.

High-dose valacyclovir can be prescribed off-label by maternal-fetal medicine specialists to help prevent the virus from passing to the fetus.

“We might have had a completely different story and not gone through the horror we have over the last two years,” Kennedy said.

Kennedy, now 39 weeks pregnant, is taking every hygiene precaution, even though her risk is much lower given she has previously contracted CMV. Her four-year-old son Jack knows not to share his food or kiss his mother near her lips.

CMV is usually harmless or causes mild flu-like symptoms, and roughly 85 per cent of the population contracts CMV at some point in their lifetime. But if a woman contracts CMV just before or during pregnancy, there is a risk that her unborn baby will also become infected.

An estimated 2 per cent of pregnant women will contract CMV for the first time during pregnancy, and roughly one in three will pass on CMV to their unborn baby.

Most fetuses that contract CMV will develop normally, but about 15 per cent of these babies will develop a CMV-related disability by their fifth birthdays.

Pregnant women with young children are at increased risk of CMV because toddlers and preschoolers are prone to catching and transmitting the virus to their mothers via intimate contact.

The Royal Australian College of Obstetricians and Gynaecologists released recommendations for the prevention of CMV infection in 2019 but Kate Daly, president of CMV Australia, said the message still wasn’t cutting through.

“Every pregnant woman has the right to know about CMV,” Daly said. “There is no one more motivated to follow health advice than a pregnant woman, and the fact that women going through IVF have not heard of CMV is crazy to me.”

June is CMV Awareness Month.

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