CMV screening in pregnancy is now recommended for every pregnant woman whose cytomegalovirus status is unknown or negative. The Haute Autorité de santé (HAS, the French national health authority) made this decision in June 2025, within a trial framework to be reassessed after three years. On 4 August 2026, it published the care guidelines that go with this screening.
This article sums up those two publications. It explains why the HAS changed its position, when the blood tests should be done, what happens if a recent infection is found and which everyday habits lower the risk. It does not replace the advice of the midwife or doctor who is following your pregnancy.
What is cytomegalovirus?
Cytomegalovirus, or CMV, is a very common virus. According to the HAS, around 46 % of women aged 15 to 49 in France have already been in contact with it. This figure can reach 90 % in France's overseas departments and regions.
It spreads through bodily fluids: saliva, respiratory secretions, urine, tears, genital secretions and breast milk. Young children are a frequent source, because they shed the virus in their saliva and urine. In 90 % of cases, the infection causes no symptoms and has no consequences for either the mother or the baby.
Why is CMV monitored during pregnancy?
The main risk comes from a first infection caught in the two months before pregnancy or during the first trimester. The virus can then pass to the baby and leave lasting effects. The HAS mentions hearing loss in one or both ears, neurological symptoms, neurodevelopmental disorders and balance problems.
These serious complications remain uncommon. The HAS puts them at between 1 and 6 children per 100,000 births. Santé publique France (the French public health agency) notes that few women receive prevention advice about this virus, as our article on congenital anomalies points out.
What has changed: from no screening to routine screening
For years, France did not recommend this screening. The Haut Conseil de la santé publique (the French High Council for Public Health) advised against it in 2018 and again in 2023, as there was not enough evidence to show a benefit. In practice, though, around a third of pregnant women were tested anyway, with wide differences from one region to another.
On 17 June 2025, the HAS recommended routine screening for all pregnant women whose status is unknown or negative. It gives several reasons:
- the burden of infection during pregnancy;
- unequal access to screening across regions;
- the availability of a test and a treatment that can limit transmission to the baby;
- changes in scientific knowledge and in what society expects.
The recommendation is part of a trial framework. It will be reassessed after three years, based on the data collected in the meantime. National seroprevalence, the long-term safety of the treatment and the reliability of the tests will all be part of the review.
CMV screening in pregnancy: when are the blood tests done?
Screening relies on serology, meaning a blood test that looks for two types of antibodies, IgG and IgM. The guidelines of 4 August 2026 set out the following timetable.
Before pregnancy
If you are planning a pregnancy, the serology should be done before conception, including during assisted reproduction treatment. If it suggests a recent infection, a second blood test confirms the result. Trying for a baby is then postponed by two months.
During pregnancy
- Serology never done or negative: it should be carried out as early as possible, before 14 weeks of pregnancy (counted from the first day of the last period).
- Negative result: the woman has never met the virus. The serology is repeated every 4 weeks during the first trimester, ideally in the same laboratory.
- Last check: between 13 and 14 weeks of pregnancy.
- Positive result from a past infection: a previous infection needs no extra follow-up during pregnancy.
Beyond 14 weeks of pregnancy without serology, the HAS considers that screening is no longer relevant. It also points out that a blood test only detects a first infection: a reinfection remains invisible.
What happens if a recent infection is found?
News of a recent primary infection leads to a dedicated appointment. The professional following the pregnancy contacts an expert team, in particular a multidisciplinary prenatal diagnosis centre. The aim is a shared decision, made with all the useful information.
- The treatment: an antiviral, valaciclovir, should be started quickly, as early as possible in the first trimester. It limits transmission of the virus to the baby. The available data show no sign of birth defects linked to this treatment.
- The prescribing framework: valaciclovir is used off-label for this indication. A compassionate prescribing framework is being drafted by the ANSM (the French medicines agency).
- Amniocentesis: it is offered as early as possible from 18 weeks of pregnancy, to look for the virus in the baby.
- What comes next: if the virus is not found, the treatment stops and standard follow-up resumes. If it is found, the pregnancy is followed with the prenatal diagnosis team.
Which everyday habits lower the risk?
The HAS asks for all women who are pregnant or hoping to be, and their partner, to be informed early. The recommended habits focus on young children’s saliva and urine:
- wash your hands regularly, especially after a nappy change or wiping a nose;
- don’t share cutlery, glasses or toothbrushes;
- don’t put in your mouth anything that has touched a child’s saliva, such as a dummy or a spoon;
- avoid kissing young children on the mouth;
- regularly clean surfaces soiled with saliva or urine.
These precautions matter especially for women working in early childcare, whether in a nursery, a drop-in crèche or as a childminder. They also apply to families where an older sibling attends a group setting, where viruses circulate a lot, as described in our article on babies falling ill at nursery. Handwashing steps, which are worth teaching older siblings too, are covered in our article on learning to wash hands.
After birth: hearing follow-up
Hearing loss is the most frequently cited after-effect of congenital CMV infection. A hearing screening test is offered to all newborns in the maternity unit. The other checks carried out at birth are presented in our article on newborn screening. A child exposed to the virus during pregnancy receives specific follow-up decided by the medical team.
In everyday life, watching how your baby reacts to sounds is still useful. The main milestones are described in our article on hearing development. Any concern about development, hearing or balance should be discussed with the doctor, as explained in our feature on spotting neurodevelopmental disorders.
What is still to come
Several elements are not yet in place at the time of writing. The compassionate prescribing framework for valaciclovir is being drafted by the ANSM. The HAS would like midwives to be able to prescribe this treatment in the future. It has also proposed updating the list of reimbursed laboratory tests, and announced an information leaflet for pregnant women for October 2026.
In summary
- Since June 2025, the HAS has recommended CMV screening for all pregnant women who are not immune or whose status is unknown.
- Serology is done before 14 weeks of pregnancy, then every month in the first trimester if it is negative.
- A recent infection leads to a dedicated appointment and treatment with valaciclovir.
- Hygiene habits around young children’s saliva and urine remain the first line of protection.
- The scheme will be reassessed after three years.
Sources
- Haute Autorité de santé, press release of 17 June 2025. “Cytomégalovirus (CMV) chez la femme enceinte : la HAS recommande un dépistage systématique pour toutes à réévaluer après 3 ans de mise en œuvre”.
- Haute Autorité de santé, “La HAS précise les modalités de prise en charge de la femme enceinte à la suite du dépistage du CMV”, press release of 4 August 2026.
