Birthweight
Birthweight is an important indicator of an infant’s health. Low birthweight has been associated with an increased risk of illness and death in infancy and into adulthood (World Health Organization 2022). Long-term health risks have also been associated with high birthweight (Magnusson et al. 2021).
Between 2010 and 2023, the rate of low birthweight (less than 2,500 grams) for all babies (both liveborn and stillborn) remained between 6.7% and 7.2%. In 2023, it was 7.2% for all babies – 6.6% of liveborn babies and 77% of stillborn babies.
In 2023, 92% of liveborn babies were born with a normal birthweight (between 2,500 and 4,499 grams). This proportion has been stable since 2010.
In 2023, 1.3% of babies were of high birthweight (4,500 grams or more). Over time, this proportion gradually decreased from 1.8% in 2010 to 1.1% in 2018 and 2019, before increasing slightly and reaching 1.3% in 2023.
Figure 1 presents trend data on the birthweight of liveborn babies, by selected maternal and baby characteristics, between 2010 (or earliest available year of data) and 2023. Select the ‘Current data’ button to view 2023 data.
Figure 1: Proportion of liveborn babies, by birthweight and selected topic
Bar chart shows birthweight by selected topics and a line graph shows topic trends between 2010 (or earliest available year of data) and 2023.
In 2023, over 1 in 7 (15%) liveborn low birthweight babies weighed less than 1,500 grams and 6.6% of liveborn low birthweight babies weighed less than 1,000 grams.
Pre-term birth (gestational age before 37 completed weeks) is closely linked with low birthweight – more than half (57%) of liveborn low birthweight babies were pre-term and over two-thirds (70%) of pre-term babies were of low birthweight.
The proportion of liveborn low birthweight babies was higher among babies born to mothers who lived in the lowest socioeconomic areas (7.9%) than babies born to mothers who lived in the highest socioeconomic areas (5.6%).
Internationally, the proportion of low birthweight babies in Australia in 2016 was the same as the OECD average for 2017 or nearest year (both were 6.5%) (OECD 2019).
Figure 2 presents the number and proportion of liveborn babies who were low birthweight, by PHN area and SA3, in 2023.
Figure 2: Proportion of liveborn babies who had a low birthweight, by selected geography
Map shows proportion of low birthweight babies by selected geographies between 2013 and 2023.
In 2023, the proportion of liveborn babies who had a low birthweight ranged from 5.5% (in Northern Sydney) to 8.0% (in both the Northern Territory and Northern Queensland) across PHNs, and from 2.8% (in Noosa) to 16% (in Gascoyne) across SA3s.
For more information on:
- livebirths by birthweight and state and territory, see National Perinatal Data Collection annual update data table 3.9
- births by birthweight and birth status, see National Perinatal Data Collection annual update data table 3.10
- livebirths by birthweight and plurality, see National Perinatal Data Collection annual update data table 3.11
- birthweight by selected maternal and baby characteristics, see National Perinatal Data Collection annual update data visualisations table 5.2
- liveborn babies who were low birthweight by Primary Health Network area and Statistical Area Level 3, see National Perinatal Data Collection annual update data tables 5.5 and 5.11
- related National Core Maternity Indicators, see Babies weighing less than the third centile.
Magnusson Å, Lauvuori H, Loft A, Oldereid NB, Pinborg A, Petzold M, Romundstad LB, Söderström-Anttila V and Bergh C (2021) ‘The association between high birth weight and long-term outcomes-Implications for assisted reproductive technologies: A systematic review and meta-analysis’, Frontiers in Pediatrics, 9:675775, doi:10.3389/fped.2021.675775.
OECD (Organisation for Economic Co-operation and Development) (2019) Health at a glance 2019: OECD indicators, OECD, accessed 13 April 2021.
WHO (World Health Organization) (2022) WHO recommendations for care of the preterm or low-birth-weight infant, WHO, accessed 26 June 2025.