Skip to content

Infants are considered low birthweight if they are born weighing less than 2,500 grams1. This can be related to birth before 37 weeks of completed gestation (preterm low birthweight), growth restriction in the uterus (low birthweight for gestational age) or a combination of both1,2. Low birthweight is associated with increased risk of poor health, disability and death in infancy and, increased risk of health problems later in life1-3. It can therefore be used as an indicator of the health of infants at birth and understood as a determinant of their ongoing wellbeing2.

The likelihood of an infant being born low birthweight because of preterm birth is increased by multiple birth (twins and higher), maternal Indigenous status, maternal smoking during pregnancy, maternal residence in remote area and maternal age (under 20 or over 40)2,4.

On an individual level, low birthweight is a risk factor for physical and neurological disabilities and increased vulnerability to illness and disease throughout the lifespan2.

Since low birthweight is associated with a range or maternal and infant health factors it can be used to evaluate and improve pre and postnatal care for mothers and babies1,2.


  1. Australian Institute of Health and Welfare [Internet]. Canberra ACT. Mothers and Babies Reports, 2018. [cited 2018 May 16]. Available from:
  2. Australian Institute of Health and Welfare [Internet]. Canberra ACT. Mothers and Babies Overview, 2018 [cited 16 May 2018]. Available from:
  3. Stanford Children’s Health [Internet]. Palo Alto, CA. Low Birthweight. 2018 [cited 16 May 2018]. Available from:
  4. Goldenberg RL, Culhane JF, Iams JD, Romero R. Epidemiology and causes of preterm birth. The Lancet, 2008; 371(9606):75-84. Available from:

Data Source 

Compiled by Telethon Kids Institute based on Midwives Notification System, Department of Health Western Australia


Babies (live born) weighing less than 2500 grams at birth


All live births

Unit of Measure 

Per cent (%)



Data Confidentiality

Areas with count values 1 to 4 and where population is less than 50 have been suppressed.

Prior moving averages combine a sequence of 3 or 5 years of data prior to, and including, the selected year. The series are presented as overlapping sequences until the most recent year is included. Moving averages make it possible to combine more years of data to maximize sample size at each point while maintaining data confidentiality.


Includes children born in Western Australia only.