Cytomegalovirus is a very common virus, better known as CMV. It's a member of the herpes family , and often goes unnoticed... However, it shouldn't be overlooked: in fact, it's the virus most responsible for infections transmitted from mother to child. Why is it so important? What are the causes, symptoms and treatments? We explain!
What is cytomegalovirus?
Cytomegalovirus (CMV) is a viral micro-organism found only in humans. In fact, it is the most common infection transmitted from mother to baby during pregnancy.
CMV belongs to a family of viruses known as herpes viruses. Other diseases in this family include herpes simplex, Epstein-Barr virus and chickenpox or shingles.
An estimated 50-60% of women of childbearing age have already been in contact with CMV. This means that they are immune, even if this does not prevent secondary infection and they are not protected.
What are the symptoms of cytomegalovirus?
In the vast majority of cases, CMV infection is asymptomatic.
However, when symptoms are present, they strongly resemble those of the flu, with fever, fatigue, aches and pains, sore throat and headaches. However, the duration of the effects of the disease is longer than that of the flu: from 2 to 12 weeks. People are contagious until they have gone into complete remission.
Don't worry: for healthy adults, complications are rare. In children, the virus often takes the form of a cold. When it manifests itself in a more severe form, it's time to see a doctor.
What are the origins of CMV infection?
CMV is transmitted from human to human. It is transmitted through the body's secretions: saliva, urine, breast milk, nasal secretions, blood and intimate secretions. Contamination occurs through contact with secretions containing the virus. It is contagious and often infects young children.
Risk for people in contact with children
The risk is all the greater for people in contact with children, such as those working in day-care centers.
Why is cytomegalovirus dangerous during pregnancy?
The virus can be dangerous during pregnancy. Indeed, if a pregnant woman contracts the virus for the first time during her pregnancy, the infection can be dangerous for the baby.
There is also a risk of re-infection or reactivation in a woman who was previously immune.
CMV is not inevitable: even if you contract it, your baby will not necessarily be affected. Estimates tell us that in around 40% of cases, the fetus is also contaminated. In this case, we speak of congenital CMV infection. This equates to 1,500 cases a year.
Another reassuring figure: in 80% of cases, contaminated children show no symptoms. 10% will have a severe prenatal infection (i.e. microcephaly, hydrocephaly or intracranial calcifications), while 10% will be apparently healthy at birth, but will unfortunately suffer neurosensory sequelae later in life.
The risk to the fetus is greatest in early pregnancy, when the consequences of infection can lead to more serious sequelae.
How can I be screened for cytomegalovirus?
There is no automatic organized screening in European countries (including France). The only things that are recommended are hygienic measures to reduce the risk of contracting CMV infection during pregnancy .
However, a diagnosis can be made if you present symptoms typical of the virus, such as fever, severe fatigue, joint pain, malaise, etc.
If the pregnant woman shows abnormalities on ultrasound that are suggestive of the virus, or if there is a CMV infection in the pregnant woman's entourage.
The test used to determine whether a person has contracted CMV is a serological diagnosis, which detects the presence of IgG and IgM antibodies in a blood sample taken during pregnancy.
Positive CMV result: what to do?
If the blood test result shows CMV infection, amniocentesis can be performed. This will detect whether the CMV virus is present in the amniotic fluid. If it is not detected, then the mother can rest assured. If, on the other hand, the virus is detected, the mother will be closely monitored by a medical team, with monthly ultrasounds to detect any abnormalities.
If no abnormalities are detected, the pregnancy can continue as normal. In the event of anomalies being discovered, the decision whether or not to consider a medical termination of pregnancy obviously rests with the parents.
How is CMV infection treated?
At present, there is no specific treatment or vaccine to cure the infection. This is why mass screening is not an option, except before or during pregnancy for those at risk. The best solution at present remains prevention of the virus.
Preventing cytomegalovirus: what are the key precautions?
To avoid transmission of the cytomegalovirus, the best thing to do is to apply barrier measures and strict hygiene practices, and to reinforce information. These include
- Regular hand-washing, especially when changing a child (before and after changing diapers, which contain the baby's urine).
- Regularly washing baby's toys
- Don't taste baby's food with the same spoon
- Don't share baby's toiletries
- Do not take baths with them (as there is a risk of urine contamination).
- In general, avoid contact with fluids that potentially carry the virus: saliva, tears and urine.
These recommendations are particularly applicable to pregnant women, who are in contact with children aged 3 or under in their family or professional environment, and who are in a group day-care setting.
FAQs on CMV in pregnancy
Does cytomegalovirus immunity protect the fetus?
It is estimated that 50 to 60% of women of childbearing age have already been in contact with CMV. They are immune, but a secondary infection may develop. Immunity is not protective.
Is CMV contagious?
CMV is an extremely contagious virus, and the most common maternal-fetal infection. It is transmitted from mother to fetus. Women with the virus are contagious, but this is not serious in adults. It is important to keep an eye on infants.
How do I know if my fetus is infected with CMV?
If you've tested positive for CMV and you're wondering whether your fetus has been contaminated, you can have an amniocentesis.
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