Case Definition
A congenital anomaly is defined as any defect, probably originating before birth, and includes structural, chromosomal, genetic and biochemical defects and malformations. Each anomaly (with no maximum limit per child) is coded using the ICD10 classification system. Cases notified to the Register as having a syndrome are coded as such. In addition the specified individual anomalies are also coded. Anomalies that have not been confirmed by clinical or diagnostic tests are recorded as such and followed up for confirmation. These suspected anomalies are largely confined to those anomalies found on ultrasound examination in pregnancies that have not yet delivered. Ultrasound diagnosed soft markers are also notified to the registers used in the evaluation of prenatal diagnosis and screening.

Data are collected concerning any live birth, stillbirth or termination of pregnancy diagnosed and notified as having any or a specific congenital anomaly, born to residents of geographically defined populations covered by each register.

Ascertainment of Data
The BINOCAR registers need to achieve high levels of ascertainment for and completeness of information about congenital anomalies in order to be effective. This is only achieved if they collect information from multiple sources. These sources include cytogenetic laboratories, chemical pathology laboratories, post-mortem reports, coroner’s reports, parents, ultrasound departments, delivery suites, obstetric notes, neonatal units, child health systems, in-patient administration systems and paediatric notes.

The majority of notifications are received on each Register’s own notification form (example included with the MREC application). Other notifications are received from birth notifications, maternity discharge forms, cytogenetics laboratories, neonatal screening and post-mortem reports, CEMACH notifications, other anomalies registers and NCAS notification forms. An example of the data flows to and from Registers is provided in an example with the MREC application. All notified anomalies are recorded in the Register. These include confirmed, probable and suspected anomalies and antenatally diagnosed ‘soft markers’. The majority of anomalies are notified either antenatally or soon after birth. At present we receive relatively few notifications of anomalies diagnosed later although all registers are open for later notifications, in theory up to the age of 16 years.

Notifications relating to the same case from multiple sources are encouraged since this maximises the details available. Different notifiers often encounter an affected pregnancy at different stages of the pregnancy and after birth when additional and different details can be provided. Multiple source notification thus enables our records to be continually updated and validated. On-going notification beyond birth and into childhood also offers considerable advantages over the national system that traditionally relied solely on birth notification forms, and was therefore limited to reporting only anomalies evident at birth. This aspect of the registers has assumed even greater importance following the introduction of the new electronic birth notification form throughout the United Kingdom in October 2002, which does not include details of anomalies diagnosed at birth.