Birthweight adjusted for gestational age
A baby may be small due to being born early (pre-term) or be small for gestational age, which indicates a possible growth restriction within the uterus. Poor fetal growth is associated with increased risk of stillbirth and with fetal distress during labour, and may increase the risk of to developing long-term health conditions later in life (AIHW 2022).
Adjusting birthweight for gestational age allows for differences in a baby’s growth status and maturity to be considered when examining their health at birth (AIHW 2022).
Babies are defined as being small for gestational age if their birthweight is below the 10th percentile for their gestational age and sex, and babies are defined as large for gestational age if their birthweight is above the 90th percentile for their gestational age and sex, as determined by national percentiles. Data on birthweight adjusted for gestational age is limited to liveborn singleton babies (AIHW 2022).
In 2020, 12% of babies of Aboriginal and Torres Strait Islander mothers were small for gestational age, 73% of were a normal size for gestational age and 10% were large for gestational age (compared with 8.7%, 78% and 9.3% of babies of non-Indigenous mothers).
Between 2013 and 2020, the proportion of babies of Aboriginal and Torres Strait Islander mothers who were by birthweight adjusted for gestational age group has remined largely unchanged, from 12% to 14% for small for gestational age, from 73% to 74% for normal size for gestational age and from 8.8% to 10% for large for gestational age.
The data visualisation below shows the proportion of liveborn singleton babies of Aboriginal and Torres Strait Islander mothers and non-Indigenous mothers by birthweight adjusted for gestational age group, and the proportion of liveborn singleton Aboriginal and Torres Strait Islander babies and non-Indigenous babies by birthweight adjusted for gestational age group from 2013.
Figure 1: Proportion of babies of Aboriginal and Torres Strait Islander mothers, babies of non-Indigenous mothers, Aboriginal and Torres Strait Islander babies and non-Indigenous babies, by birthweight adjusted for gestational age group from 2013 to 2020
Line graph of birthweight adjusted for gestational age by Indigenous status. Most babies of Aboriginal and Torres Strait Islander mothers were a normal size for their gestational age.
Bar chart for birthweight adjusted for gestational age by selected topics. 73% of babies of Aboriginal and Torres Strait Islander were a normal size for their gestational age.
