Data sources

The National Congenital Anomalies Data Collection

The NCADC is a national data collection on babies with a congenital anomaly. It is based on cases of congenital anomalies reported to state and territory data collections, including congenital anomaly registers, perinatal data collections and admitted patient data collections. Data from Western Australia and the Northern Territory are not yet available as part of this collection. More information about jurisdictional congenital anomaly data sources can be found in ‘State and territory data collections’.

Some baby and maternal data elements in the NCADC are sourced from the NPDC. Jurisdictions provide a common identifier so cases with congenital anomalies in the NCADC can be linked to their respective NPDC record.

Collection and reporting scope

The scope of the NCADC includes births (both live births and stillbirths) with a congenital anomaly and terminations of pregnancy due to a congenital anomaly (if this is available). This includes conditions in the ninth edition of the ICD10-AM, including Chapter 17 (Q00-Q99), P35 (congenital viral diseases) and P371 (congenital toxoplasmosis). In practice, what can be supplied varies by jurisdiction and this impacts national reporting. The AIHW has harmonised the data for reporting, so the scope for reporting from the NCADC is narrower than the scope for the collection as a whole.

  • Congenital anomaly data supplied using the Royal College of Paediatrics and Child Health’s Classification of Diseases (ICD-9-BPA) classification (this included all data from South Australia and some records from New South Wales) were mapped to the ICD-10-AM (ninth edition) to report data on a single classification.
  • The notification period for this report includes anomalies diagnosed up to 12 months of age as all jurisdictions, except Tasmania, could supply this data; Tasmania could supply data for the birthing episode only. Some, but not all, jurisdictions collect data based on notification periods greater than 12 months. For example, South Australia collects anomalies data in children up to 5 years of age. Analysis of the data supplied by South Australia in 2016 indicates around 10% of anomalies in their 2016 birth cohort were diagnosed after 12 months of age and were excluded from this national report.
  • Some anomalies were excluded from national reporting because they were not collected across all jurisdictions or because they did not pose significant health concerns for a baby in the first year of life or have major social or cosmetic outcomes. Excluded anomalies were based primarily on those listed by the World Health Organization (WHO), the United States Centers for Disease Control and Prevention (CDC) and the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR). A list of reporting exclusions (PDF 365kB) is attached for information
  • Terminations of pregnancy before 20 weeks’ gestation were excluded as these data were not available across all jurisdictions.
  • Only records able to be linked to the NPDC were included for reporting.