Eurocat NNL is a population-based congenital anomaly registry covering Groningen, Friesland, and Drenthe in the Northern Netherlands from 1981 onwards. All pregnancy outcomes are covered and information is collected on genetic testing, prenatal diagnosis, and risk factors through parental questionnaires (response percentage around 80%), medical records, and pharmacy data. All children and foetuses with a congenital anomaly whose mother was a resident of Groningen, Friesland, or Drenthe at the time of birth are included. Registration is an ongoing process; children can be registered until 10 years after birth and at all gestational ages. Still births, miscarriages, and terminations of pregnancy are also included in the registry.

Recruitment is ongoing