Birthweight is an important indicator of an infant’s health. Nine in ten babies (92%) were born with a normal birthweight (birthweight between 2,500 and 4,499 grams). Around 1% of babies are high birthweight (birthweight of 4,500 grams or more).

Low birthweight (birthweight less than 2,500 grams) has been associated with increases in illness and death in infancy and into adulthood. In 2019, 7.2% of all babies were low birthweight—6.6% of liveborn babies and 84% of stillborn babies.

The figure shows a bar chart of the proportion of liveborn babies by birthweight by a range of topics for 2019. The figure also shows a line graph of trends within birthweight categories by a range of topics over 2009 to 2019. In 2019, 6.6% or 19,982 liveborn babies had a low birthweight.

14.6% of liveborn low birthweight babies weighed less than 1,500 grams and 6.4% of liveborn low birthweight babies weighed less than 1,000 grams.

Pre-term birth is closely linked with low birthweight—over two thirds (68%) of liveborn low birthweight babies were pre-term (gestational age before 37 completed weeks) and more than half (57%) 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 (8.0%) than babies born to mothers who lived in the highest socioeconomic areas (5.6%).

Internationally, the proportion of low birthweight babies in Australia in 2017 or nearest year (6.5%) was equal to the OECD average (6.5%), with Australia ranked equal 19th of 36 OECD countries (OECD 2019).

For more information on birthweight see National Perinatal Data Collection annual update data tables 3.9 and 3.10.

For related information see National Core Maternity Indicator Small babies among births at or after 40 weeks of gestation


OECD (Organisation for Economic Co-operation and Development) 2019. Health at a glance 2019: OECD indicators. Paris: OECD Publishing. Viewed 13 April 2021.