Technical notes
Terminology
Sex and gender terminology
This report uses the terms ‘woman’, ‘women’, ‘mother’ and ‘mothers’ to mean females who were pregnant or gave birth. ‘Woman’ and ‘women’ typically refers to groups of people aged 18 years and over; however in this report, people who were pregnant or gave birth aged less than 18 are included.
It is acknowledged that this report includes people who do not identify as women or mothers, and that individual parents and families may use different words to those used in this report. This may include transgender men, intersex people, non-binary and gender diverse people.
First Nations terminology
The AIHW uses ‘First Nations people’ to refer to Aboriginal and/or Torres Strait Islander people in this report.
Data sources
National Perinatal Data Collection
Analysis in this report uses data from the National Perinatal Data Collection (NPDC) for 2020 and 2021, including voluntary mental health screening items contributed by states and territories under the 2020–21 and 2021–22 National Best Endeavours Data Set (NBEDS).
See Availability of perinatal data for more information about what perinatal data are available in the NPDC and NBEDS.
See Australia's mothers and babies for more information on how data are collected for the NPDC and its structure.
Methods
Analysis in this report and supporting data tables presents maternal and pregnancy characteristics of:
- all mothers who gave birth in Australia between 2020 and 2021
- all mothers who gave birth in Queensland, Tasmania and the Australian Capital Territory
and the maternal and pregnancy characteristics, and EPDS screening results for:
- all mothers who gave birth in Queensland, Tasmania and the Australian Capital Territory and had a recorded antenatal mental health screening result.
Proportions, percentages and rates for maternal characteristics exclude cases where the variable of interest is missing, recorded as not stated, or is inadequately described.
New South Wales, South Australia, Western Australia, and the Northern Territory did not supply data on the use of assisted reproductive technologies to the NPDC for 2020–2021.
New South Wales and Western Australia did not supply data on previous pregnancies resulting in live birth and previous still birth to the NPDC for 2020–2021.
New South Wales did not supply data on alcohol consumed during first 20 weeks and alcohol consumed after 20 weeks to the NPDC for 2020–2021.
States and territories that did not supply data for specific data items are excluded from the calculations for all mothers.
Where a pregnancy resulted in multiple births (twins, triplets, and so on), birth setting and gestational age from the first birth are reported. Where any birth resulted in stillbirth, birth outcomes are reported as ‘any stillbirth’. Birth outcomes are reported as ‘all live births’ where all babies were live born, regardless of subsequent survival or death in the perinatal and postnatal periods.
This report uses the Australian Statistical Geography Standard (ASGS) Remoteness Structure which classifies geographical areas based on their relative access to services.
Remoteness Areas are assigned to the smallest statistical geography unit in the ASGS, Statistical Area 1 (SA1), describing an area with a population of between approximately 200 and 800 people.
This report uses ASGS Remoteness Areas mapped to the Statistical Area 2 (SA2) of mother’s usual residence. As Remoteness Areas are assigned at the SA1 level, which aggregate to form SA2s, some SA2s include more than one Remoteness Area. For mothers in an SA2 containing more than one Remoteness Area, counts of mothers were proportionally assigned based to Remoteness Areas based on the estimated percentage of persons in each Remoteness Area within the SA2.
In this report, remoteness is not reported for mothers not usually resident in Australia or where the mother’s SA2 or state of usual residence was not stated, inadequately described, was unable to be mapped to a Remoteness Area, or was in a territory other than Northern Territory or Australian Capital Territory. Table 3 shows the number of mothers for whom remoteness is not reported.
Table 3: Mothers excluded from remoteness reporting by state and territory of baby’s birth
State of baby’s birth | N (%) |
|---|---|
New South Wales | 1,582 (0.8) |
Victoria | 162 (0.1) |
Queensland | 64 (0.1) |
South Australia | 33 (0.1) |
Western Australia | 1,221 (1.9) |
Tasmania | — |
Northern Territory | 4 (0.1) |
Australian Capital Territory | 1 (0.0) |
See the Australian Statistical Geography Standard (ASGS): volume 5 - remoteness structure, July 2016 (ABS 2018a) for further information on Remoteness Areas.
The Socio-Economic Indexes for Areas (SEIFA) summarises a range of variables to rank geographic areas of Australia according to relative socio-economic advantage or disadvantage. This report uses the 2016 Index of Relative Socioeconomic Disadvantage (IRSD) developed by the Australian Bureau of Statistics for use at Statistical Area Level 2 (SA2), defined geographic areas generally containing between 3,000 and 25,000 people.
The IRSD is a summary measure for a geography area and describes the average level of disadvantage in that area. Socio-economic advantage and disadvantage varies at the individual level within each SA2. A SEIFA rank does not apply to an individual but summarises characteristics of the geographic area such as income and opportunities in education and employment.
This report uses SEIFA quintiles, five approximately equal sized groups ranking geographic areas from the least advantaged (Q1) to the most advantaged (Q5). Mothers are classified into SEIFA quintiles based on their SA2 of usual residence.
In this report, SEIFA scores are not reported for mothers not usually resident in Australia or where the mother’s SA2 or state of usual residence was not stated, inadequately described, was unable to be mapped to a SEIFA score, or was in a territory other than Northern Territory or Australian Capital Territory. Table 4 shows the number of mothers for whom SEIFA is not reported.
Table 4: Mothers excluded from SEIFA reporting by state and territory of baby’s birth
State of baby’s birth | N (%) |
|---|---|
New South Wales | 1,701 (0.9) |
Victoria | 204 (0.1) |
Queensland | 66 (0.1) |
South Australia | 272 (0.7) |
Western Australia | 1,263 (1.9) |
Tasmania | — |
Northern Territory | 25 (0.3) |
Australian Capital Territory | 317 (2.6) |
See Socio-Economic Indexes for Areas (SEIFA), Australia, 2016 (ABS 2018c) for further information on SEIFA.
Country of birth is recorded using the Standard Australian Classification of Countries (SACC) a four-digit hierarchical structure classifying countries into major and minor groups country. Mothers born in Australia are identified using the minor group and country codes for Australia and its external territories (11, 1101, 1102 & 1199).
Gestational age uses the number of completed weeks of pregnancy at the time of birth. In this report, mothers were classified as pre-term if they gave birth at between 20 and 36 completed weeks of pregnancy, as at term if they gave birth between 37 and 41 weeks, and post-term if they gave birth at 42 or more completed weeks of pregnancy.
Age-standardised rates enable comparisons to be made between populations that have different age structures. Data tables for this report include age-standardised rates using direct standardisation, in which the age-specific rates are applied to a constant population.
Age-standardised rates in supporting data tables use the June 2001 Australian female estimated resident population aged 15–44 as the reference population using five-year age groups. Limited 10-year age groups were used for some characteristics due to small numbers (Table 5).
Age-standardised rates are not reported for post-term births due to small numbers.
Table 5: Age groups used for age standardisation, by maternal characteristic
Characteristic of mother or pregnancy | Age groups |
|---|---|
Alcohol consumed after 20 weeks, Parity, Previous live births, Previous stillbirth | 15–24, 25–29, 30–34, 35–39 and 40–44 |
Birth setting, Remoteness Area | 15–19, 20–24, 25–29, 30–34, 35–44 |
Birth outcomes, Use of assisted reproductive technology | 15–24, 25–29, 30–34, 35–44 |
Alcohol consumed during first 20 weeks, Diabetes during pregnancy, Indigenous status, Gestational age, Hypertensive disorder during pregnancy, Mother’s country of birth, Multiple births, Pre-pregnancy BMI, Socioeconomic status (SEIFA quintile), Smoked after 20 weeks, Smoked at any point, Smoked during first 20 weeks | 15–19, 20–24, 25–29, 30–34, 35–39 and 40–44 |
Australian Bureau of Statistics (ABS) (2018a) Australian Statistical Geography Standard (ASGS): volume 5 - remoteness structure, July 2016, ABS, Australian Government, accessed 26 September 2023.
ABS (2018c) Socio-Economic Indexes for Areas (SEIFA), Australia, 2016, ABS, Australian Government, accessed 26 September 2023.