Congenital anomalies affect around 2.5% of all pregnancies. Many of these anomalies are suspected before birth following an ultrasound examination, or diagnosed as a result of an invasive prenatal diagnostic test such as chorion villous sampling (CVS) or amniocentesis. Such testing may be carried out because of a high risk screening test result, a family history of anomalies or an abnormal ultrasound scan.

Many European countries offer screening in the first trimester of pregnancy. This includes a 12 week scan to measure the nuchal translucency which, combined with pregnancy specific blood test results, will provide a risk for trisomies 21, 18 and 13 (Down, Edwards and Patau syndromes). Those receiving a high risk may then opt for an invasive test to check the fetal chromosomes.

The number and types of anomalies suspected before birth will depend on what tests are available, the experience of the operator and the accuracy of the particular test. All of these factors are continually changing and vary between centres and countries.

EUROCAT Registries collect information on whether an anomaly was suspected prenatally, the gestational age at first suspicion, the type of test that led to that suspicion and the outcome of the pregnancy. Monitoring detection rates for different anomalies, the types of tests used and the outcome of affected pregnancies (livebirth, termination of pregnancy) is an important part of the work carried out by EUROCAT.

Definition of some prenatal terms

Prenatal Diagnosis is defined as a diagnosis suspected/made in a live fetus at any gestation.

Gestational Age is the gestational age at which the fetus was first suspected to be malformed (excluding soft-markers) and indicates the time of the examination rather than the time when the result is known (see EUROCAT guide).

Technical Notes on the on the charts/tables

Information on the proportion of cases prenatally diagnosed are available for the latest five year period only.

Only registries with 80% known for the “when discovered” variable and four or more years of data in the latest time period are included in these tables.

Please refer to EUROCAT Member Registries for information on how data was collected, definitions used, and for Registry Leader contact details.

Display of EUROCAT Prenatal detection rates

In order to comply with the provisions of the General Data Protection Regulation (2016/679, "GDPR") and to protect the privacy of individuals with congenital anomalies, the EUROCAT network implemented specific rules to display small numbers on its website.

The page on prenatal detection rates presents the distribution of registries in the anomaly subgroup selected by the user for each indicator separately (e.g. overall proportion of cases prenatally diagnosed, percentage of live births among the cases prenatally diagnosed, …).

Under each graph, a reading note helps the user interpret the graph.

In case you would need further results, please contact the JRC-EUROCAT central registry ( We will evaluate your request, based on the detailed background information you can provide.


Last update: 7 December 2023