Le cytomegalovirus, or CMV, is a virus of the family of herpesvirus (which includes in particular the viruses responsible for cutaneous herpes, genital herpes and chickenpox).

It is a so-called ubiquitous virus, which is found in 50% of people in developed countries. It is often latent, causing no symptoms. In a pregnant woman, on the other hand, CMV can be transmitted to the fetus through the placenta and can cause developmental problems.

In the vast majority of cases, infection with CMV goes unnoticed. When there are symptoms, they usually appear about a month after infection and are characterized by fever, fatigue, headache, muscle pain, and weight loss. They mostly occur in people with weakened immune systems.

In pregnant women, a unexplained fever may thus justify an examination of the blood level of CMV. This is because when it infects the fetus, CMV can cause serious developmental abnormalities and even death. It is therefore necessary to detect the presence of the virus in the event of a suspected maternal-fetal infection.

In infected people, CMV is found in urine, saliva, tears, vaginal or nasal secretions, semen, blood or even breast milk.

To detect the presence of CMV, the doctor orders a blood test. The examination then consists of a blood sample from a vein, usually at the fold of the elbow. The analysis laboratory then seeks to identify the presence of the virus (and to quantify it) or anti-CMV antibodies. This analysis is prescribed for example before an organ transplant, in immunocompromised people, for screening seronegative women (who have never been infected) before pregnancy, etc. It has no real interest in a healthy person.

In the fetus, the presence of the virus is detected by amniocentesis, that is, taking and analyzing the amniotic fluid in which the fetus is located.

Testing for the virus can be done in the urine of the child from birth (by viral culture) if the pregnancy is carried to term.

If a person is diagnosed with CMV infection, they are told that they can easily pass the infection on. All you need is an exchange of saliva, intercourse, or a deposit on the hands of a contaminated droplet (sneezing, tears, etc.). An infected person can be contagious for several weeks. Antiviral therapy may be initiated, especially in immunocompromised individuals.

In France, each year, around 300 maternal-fetal infections are observed. It is the most common viral infection transmissible from mother to fetus in industrialized countries.

Of these 300 cases, it is estimated that about half lead to the decision to terminate the pregnancy. In question, the serious consequences of this infection on the nervous development of the fetus.