Data sources

National Perinatal Data Collection

The National Perinatal Data Collection (NPDC) began in 1991 and is a national population-based cross-sectional collection of data on pregnancy and childbirth. The NPDC collects national information on the pregnancy and childbirth of mothers, and the characteristics and outcomes of their babies. A standard de-identified extract is provided from states and territories to the Australian Institute of Health and Welfare (AIHW) on an annual basis to form the NPDC.

The NPDC supports a range of reports and products, including:

  •  Australia’s mothers and babies
  • National Core Maternity Indicators reports and data visualisations
  • Indigenous mothers and their babies reports
  • other specialist reports, indicator-based reports and customised data requests.

Detailed information on completeness, accuracy and other aspects of data quality for the NPDC is in the data quality statement.

Collection of perinatal data by states and territories

Perinatal data are collected after each birth, usually by midwives or other birth attendants using information obtained from mother, from clinical and administrative records and information systems, including records of antenatal care, the care provided during labour, and the delivery and care provided after the birth. Each state and territory has its own form and/or electronic system for collecting data, which are forwarded to the relevant state and territory health departments to form the state or territory perinatal data collection. See the section on State and territory perinatal data collections for state and territory contact details and the most recent state and territory perinatal reports, which contain more detailed information about data collection in each jurisdiction. The Maternity Information Matrix summarises data items from Australian national and state and territory data collections relevant to maternal and perinatal health.

Collation of national perinatal data

A standardised extract of electronic data from each state and territory collection is provided to the Australian Institute of Health and Welfare (AIHW) annually. Records received from states and territories are anonymous: that is, they do not include any names or addresses, but do include a unique set of identification numbers so that the source record can be identified. Data are checked for completeness, validity and logical errors before inclusion in the national collection.

Overview of maternal and perinatal data collections and national reporting outputs

The figure maps the interactions of different data collections, reporting outputs and metadata in relation to the National Perinatal Data Collection.

Structure of the National Perinatal Data Collection

Data supplied for the NPDC consist of the Perinatal national minimum data set (Perinatal NMDS) and additional data items.

Structure of the National Perinatal Data Collection

The figure demonstrates that the National Perinatal Data Collection can be broken down into the Perinatal National Minimum Data Set (NMDS) and additional data items. In 2019, there were 34 NMDS data elements and 75 voluntary additional data elements.

The Perinatal NMDS was first specified in 1997 and is an agreed data set for national reporting (COAG 2012). An NMDS is an agreed set of standardised data elements for mandatory supply by states and territories to support national reporting. Standardisation ensures that there is consistent meaning for data collected at different times or in different places. See the section on Perinatal national minimum data set items for a list of the data items supplied for the NPDC from the Perinatal NMDS.The Perinatal NMDS was first specified in 1997 and is an agreed data set for national reporting (COAG 2012). An NMDS is an agreed set of standardised data elements for mandatory supply by states and territories to support national reporting. Standardisation ensures that there is consistent meaning for data collected at different times or in different places. See the section on Perinatal national minimum data set items for a list of the data items supplied for the NPDC from the Perinatal NMDS.

Each state and territory collects more information than is specified in the Perinatal NMDS, and the AIHW requests some of these additional items. These data items are at different stages in the process of standardisation. Some items have had national data standards developed, but have not yet been included as data elements in the Perinatal NMDS because they could not be implemented immediately in all jurisdictions.

In contrast, there are other data items—for which there are, as yet, no common definitions or categories for collecting the data or which are not collected in all jurisdictions—that are also provided to inform the future development of nationally standardised data.

Which births are counted?

This report presents information from the NPDC about births in Australia, including births in hospitals, in birth centres and in the community. Freebirths may be included in the NPDC if they are in scope of the data collection, and the mother or baby present to hospital following birth, or the birth is registered with the Registry of Births, Deaths and Marriages. However, this differs by state and territory.

The Australian National health data dictionary defines a ‘live birth’ as the complete expulsion or extraction from its mother of a baby, of any gestation, that shows signs of life; and a ‘stillbirth’ is the complete expulsion or extraction of a baby, of at least 20 weeks’ gestation or weighing at least 400 grams at birth (the weight expected of a baby at 20 weeks’ gestational age), which shows no signs of life.

The Perinatal NMDS and the NPDC require that either the birthweight or the gestational age conditions are met for both live births and stillbirths. This means that the very small number of live births occurring before 20 weeks’ gestation and weighing less than 400 grams are not included in the NPDC, although they may have been included in jurisdictional perinatal data collections. Data for babies whose gestational age and birthweight were not recorded are also not included in the NPDC, but may have been included in jurisdictional perinatal collections. Live births and stillbirths may include termination of pregnancy after 20 weeks. Stillbirths can include fetus papyraceous and fetus compressus (products of conception recognisable as a deceased fetus). In Victoria and Western Australia, data were included for both live births and stillbirths of at least 20 weeks’ gestation or, if gestation was unknown, the birthweight was at least 400 grams. South Australian data may not include all terminations of pregnancy for psychosocial reasons after 20 weeks’ gestation where birthweight was not recorded.

Care is needed when comparing Australian birth statistics with those from countries that have different gestational age or other criteria for defining live births and stillbirths. In many other countries, pregnancies must continue to 22, 24 or even 28 completed weeks of gestational age for a fetal death to be counted as a stillbirth. The inclusion in Australia of more births at lower gestations will affect the distributions of several key baby outcomes—in particular, rates of perinatal mortality, low birthweight, low Apgar scores (a measure of a baby’s wellbeing at birth) and admission to a special care nursery or neonatal intensive care unit. For live births, the Perinatal NMDS and NPDC definition is more restrictive than the World Health Organization definition that specifies a live birth as a baby born showing signs of life irrespective of gestation (WHO 1992).

National Perinatal Data Development Committee

The National Perinatal Data Development Committee has a key role in improving data quality. The committee comprises representatives from each state and territory health authority and the AIHW, with temporary members invited as their expertise is required. The committee works in consultation with clinical reference groups. It improves data provision, revises existing Perinatal NMDS items, develops existing perinatal data items in METeOR (AIHW’s Metadata Online Registry) and contributes to the development of new perinatal data items.

References

COAG (Council of Australian Governments) 2012. National Healthcare Agreement 2012. Intergovernmental agreement on federal financial relations. Canberra: COAG. Viewed 31 March 2020.

WHO (World Health Organization) 1992. International Statistical Classification of Diseases and Related Health Problems, 10th Revision. Geneva: WHO.

National Maternal Mortality Data Collection

This report is compiled from data held by the AIHW in the National Maternal Mortality Data Collection (NMMDC). Data are provided by states and territories and contain information on the deaths of women reported to have died while pregnant or within 42 days of the end of pregnancy between 2006 and 2019.  

Due to its health and privacy legislation, only limited summary data on maternal deaths from 2006–2018 were supplied by Western Australia. As these data provided are already aggregated, rather than provided by case, they cannot be included in the NMMDC but are included in analysis where possible.

Detailed information on completeness, accuracy and other aspects of data quality for the NMMDC is in the data quality statement.

National Perinatal Mortality Data Collection

The National Perinatal Mortality Data Collection (NPMDC) is a population-based cross-sectional collection of data regarding the deaths of babies in hospitals and in the community, and includes all neonatal deaths and stillbirths of a baby at least 20 weeks’ gestation or at least 400 grams birthweight, during pregnancy, birth or within 28 days of birth.

The NPMDC commenced with the 2013 birth cohort and builds on information collected in the NPDC. Common identifier fields in the NPDC and NPMDC allow demographic information regarding perinatal death records in the NPMDC to be retrieved from the NPDC for reporting.

There are 33 voluntary data items collected in the NPMDC which are supplied by state and territory health authorities using a standard de-identified extract to the Australian Institute of Health and Welfare (AIHW) on an annual basis. Data specifications supplied to jurisdictions for collection are included in the related data tables.

Detailed information on completeness, accuracy and other aspects of data quality for the NPMDC is in the data quality statement.