CMV in Pregnancy
What is CMV?
Cytomegalovirus (CMV) is a virus which causes, in most cases, a mild flu like illness in adults, but which can be associated with problems for developing babies if mothers are infected for the first time while pregnant. About 60% of pregnant women show serological evidence of past exposure to CMV, meaning about 40% have never been exposed and are at risk of contracting CMV while pregnant (particularly if they are already parents of young children who may themselves be asymptomatic). In a primary infection during pregnancy, the risk of transmission of CMV to a developing baby is about 30%, with about 10% of these babies showing symptoms after birth.
How can CMV be acquired?
Acquiring CMV as an adult or child usually requires close personal contact with an infected person as the infection is transmitted via body fluids or from surfaces contaminated with bodily fluids (saliva, urine, nasal secretions). CMV can cross the placenta and infect babies in the womb.
What are the effects on mothers and unborn babies?
Mothers’ infections are very often asymptomatic and rarely cause any problems or have any long term consequences. The effects on babies who contract CMV can vary in severity from minimal effects to neurological problems (brain, eye, hearing loss), growth restriction, heart and bowel problems, and rarely miscarriage. To confirm the infection in a mother, blood tests for antibodies against CMV are performed and if they are present, then determining whether they are newly developed or due to an infection that occurred in the past. To determine whether a developing baby has been exposed and the likelihood of infection and possible side effects, a tertiary ultrasound is performed in a specialist centre and amniocentesis may be required.
Is there any treatment for CMV?
At present, there is no consistently effective treatment for CMV, either for infected mothers or affected babies. There is no effective vaccine.
How do you avoid CMV?
- Hand washing is the single most important means of avoiding exposure, especially after activities like changing nappies, feeding or bathing children, wiping runny noses or handling toys
- Don’t share eating utensils with children
- Don’t put your child’s dummy in your mouth
- Don’t share toothbrushes with your children and try to avoid saliva when giving your child a kiss
- Clean toys and other surfaces that commonly come into contact with urine or saliva
The above information doesn’t take the place of a medical consultation so please seek further advice if you have further concerns.
Ref: Naing et al. Congenital Cytomegalovirus infection in pregnancy: a review of prevalence, clinical features, diagnosis and prevention. ANZJOG 2016; 56:9-18