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 make babies more likely to develop long-term health conditions later in life.

Adjusting birthweight for gestational age allows for differences in a baby’s growth status and maturity to be taken into account when examining their health at birth.

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 is on birthweight adjusted for gestational age is limited to liveborn singleton babies.

Babies were more likely to be small for gestational age if they were:

  • Indigenous
  • born to Indigenous mothers
  • born to mothers who live in Very remote areas
  • born to underweight mothers
  • born to teenage mothers (aged under 20)
  • born to mothers who smoked
  • born to mothers who lived in the lowest socioeconomic areas.