Congenital malformations and other major congenital anomalies affect 3.5% of births in France, or 1 in 28. That is the finding of the first national report on the subject by Santé publique France (France's public health agency), published on 8 July 2026 and covering the period 2019-2021. This rate is higher than the European average, which the agency puts at 2.7%.
The report draws on registries that record these anomalies in several areas of France. It sets out the most common types, the share diagnosed before birth, the effect of the mother's age and the main levers for prevention. Here is what it contains, and what it doesn't tell us.
What exactly are we talking about?
Santé publique France defines congenital anomalies as structural defects affecting one or more organs. They arise during pregnancy, mostly in the first trimester, when the organs are forming. The official term, ‘congenital anomalies’, is broader than malformations: it also covers genetic anomalies, including chromosomal anomalies such as Down syndrome (trisomy 21).
The report only counts so-called ‘major’ anomalies, using the criteria of the European network EUROCAT. It includes cases in foetuses, newborns and children up to one year old. It therefore also includes pregnancies that did not continue.
Congenital malformations: how many births are affected?
Between 2019 and 2021, overall prevalence was 352.5 cases per 10,000 total births. Total births include live births, stillbirths and terminations of pregnancy for medical reasons (known in France as IMG).
The figure varies by area, from 255.3 per 10,000 in the French Antilles to 397.4 per 10,000 in Brittany. It comes from five population-based registries: the Antilles, Auvergne, Brittany, Paris and La Réunion. Together they cover around 16.4% of annual births in France. The national figure is therefore an estimate based on these areas, not a full count across the whole country.
Congenital anomalies also weigh on mortality among the very young. According to the Santé publique France press kit, they account for nearly 20% of causes of infant death. We look at how these deaths have changed in our article on infant mortality in France.
Which anomalies are the most common?
Three main groups stand out, expressed per 10,000 total births:
- Congenital heart defects: 95.2 per 10,000. These are the most common.
- Genetic anomalies, chromosomal or otherwise: 78.8 per 10,000.
- Limb anomalies: 70.3 per 10,000, driven in particular by a significant rise in polydactyly, meaning extra fingers or toes.
Down syndrome (trisomy 21)
Down syndrome is the most common viable chromosomal anomaly. Its prevalence reaches 33 per 10,000 total births, compared with 26.3 in EUROCAT's European data. Among live births alone, it is 6.3 per 10,000, or roughly one case in every 1,587 live births. The report points out that this figure depends on mothers' ages, prenatal diagnosis policies and how society supports people with disabilities.
Neural tube defects
These include anencephaly, encephalocele and spina bifida. Their prevalence is 13.7 per 10,000 total births in France, compared with 11.4 in Europe. Among live births, it falls to 1.3 per 10,000, because more than 95% of these anomalies are detected before birth.
How many are diagnosed before birth?
Nearly 60% of congenital anomalies were diagnosed during pregnancy. This rate exceeds 75% for anomalies of the abdominal wall, the kidneys and urinary tract, genetic anomalies, anomalies of the central nervous system and complex heart defects.
Of all the cases recorded, 74.4% of babies were born alive. A termination of pregnancy for medical reasons took place in 24.1% of cases, and 1.5% of babies were stillborn. Terminations mainly involved genetic anomalies, followed by anomalies of the central nervous system and heart defects.
Prenatal diagnosis is not the same as the screening carried out after birth. The heel prick test looks for rare diseases that can't be seen on an ultrasound scan: we explain it in our article on newborn screening.
Does the mother's age change the risk?
Yes, but for one specific category. The prevalence of babies with at least one genetic anomaly was 8 times higher among mothers aged 40 and over than among those under 25. This link mainly concerns chromosomal anomalies such as Down syndrome.
For anomalies with no identified genetic cause, this age-related difference does not appear. The overall prevalence of these anomalies was in fact slightly higher among the youngest mothers. The report also notes rising maternal and paternal age, along with increases in obesity and gestational diabetes, which could influence certain anomalies. Our article on gestational diabetes covers this last point in detail.
Can some congenital malformations be prevented?
For some of them, yes. The best-established lever concerns neural tube defects: taking a folic acid supplement, also known as vitamin B9, reduces this risk.
- The recommendation: the Haute Autorité de santé (HAS, France's national health authority) advises taking folic acid from 4 weeks before the start of pregnancy until the end of the third month.
- The dose: 0.4 mg a day if there is no relevant history, 5 mg a day if there is a risk factor for a neural tube defect.
- The reality: according to the 2021 National Perinatal Survey (Enquête nationale périnatale), fewer than a third of women say they took it before their pregnancy. The report gives 28.3%, compared with 14.8% in 2010; the press kit rounds it to 27.2%.
The report also highlights a rise in blood folate deficiency among women of childbearing age: from 7.2% in the 2006 ENNS study to 13.4% in the 2014-2016 Esteban study. It notes that Anses (France's food safety agency) recommended the systematic fortification of flour in an expert assessment in October 2024.
Other measures relate to the period before conception and to pregnancy itself: stopping smoking and drinking alcohol, keeping vaccinations up to date and preventing infections. The press kit notes that only 15.7% of women receive advice on preventing cytomegalovirus (CMV) infection.
What these figures don't tell us
The report describes frequencies, not individual risks. The vast majority of pregnancies end with the birth of a baby without any major anomaly. A higher regional figure may also reflect more thorough detection, rather than a genuinely higher frequency.
Coverage remains partial. Santé publique France plans to add the registries for Rhône-Alpes and Nouvelle-Aquitaine, then fill in the areas not covered using data from the Assurance Maladie (France's national health insurance). This work is part of the same perinatal review as the figures on premature birth in France and the caesarean section rate.
For the families concerned, follow-up after birth is organised by the medical team, often together with a specialist centre. The child's development is then followed step by step, sometimes using adjusted milestones, such as corrected age for babies born prematurely.
Key takeaways
- Major congenital anomalies affect 3.5% of total births, according to registries covering 16.4% of births (2019-2021).
- The most common are heart, genetic and limb anomalies.
- Nearly 60% are diagnosed before birth.
- The risk of a genetic anomaly rises markedly with the mother's age.
- Folic acid, to be started 4 weeks before pregnancy, is still taken far too rarely.
Sources
- Santé publique France, ‘Surveillance épidémiologique des anomalies congénitales en France dans les territoires couverts par un registre: données 2019-2021’, report, 8 July 2026.
- Santé publique France, press kit ‘Santé périnatale: 10 années d'évolutions contrastées’, July 2026.
- Haute Autorité de santé, recommendation on folic acid supplementation, cited in the Santé publique France report.
- Inserm, Santé publique France, DREES, Enquête nationale périnatale 2021, cited in the report.
