This paper provides an overview of the birthweight of babies born to Indigenous mothers, including recent trends and information on factors associated with birthweight variation.

Summary

Almost 4% of all babies born in 2011 were to Indigenous mothers

In 2011, a total of 11,729 Indigenous mothers gave birth to 11,895 babies according to data from the National Perinatal Data Collection. These babies represented 3.9% of all births in 2011. Nearly all (99%) births to Indigenous mothers in 2011 were live births (rather than stillborn); this is the same proportion as for births to non-Indigenous mothers.

Newborns of Indigenous mothers were twice as likely to be of low birthweight

In 2011 and considering liveborn babies only:

• 12.6% of babies born to Indigenous mothers were of low birthweight (less than 2,500 grams), 86.0% were of normal birthweight (between 2,500 grams and 4,499 grams) and 1.4% were of high birthweight (4,500 grams or more)
• Indigenous mothers were twice as likely as non-Indigenous mothers to have babies of low birthweight (12.6% and 6.0% respectively)
• excluding multiple births, 11.2% of singleton babies born to Indigenous mothers were of low birthweight-2.5 times the rate for non-Indigenous mothers (4.6%)
• on average, the birthweight of singleton babies of Indigenous mothers (3,215 grams) was 191 grams lower than that of babies born to non-Indigenous mothers (3,406 grams).

Gap in birthweight has narrowed over a decade

Between 2000 and 2011, there was a statistically significant decrease in the low birthweight rate among liveborn singleton babies of Indigenous mothers, with the rate declining by 9% over the period (or by 0.1 low birthweight babies per 100 live births annually).

In contrast, there was no significant change in the corresponding rate for non-Indigenous mothers. As such, there was a statistically significant narrowing of the gap in the rate for Indigenous and non-Indigenous mothers between 2000 and 2011.

Decline in rate of pre-term births to Indigenous mothers and smoking during pregnancy

A wide range of factors are associated with birthweight, including pre-term births and maternal smoking during pregnancy. In 2011, 12.5% of liveborn babies of Indigenous mothers were born pre-term, as were 7.5% of babies born to non-Indigenous mothers. Between 2000 and 2011, the rate of pre-term births among liveborn singleton babies of Indigenous mothers declined (by 7%), and the Indigenous to non-Indigenous gap in the pre-term birth rate narrowed significantly.

Half (50%) of all Indigenous mothers who gave birth in 2011 reported smoking during pregnancy, as did 12% of non-Indigenous mothers. Smoking during pregnancy declined between 2005 and 2011, but improvement was greater among non-Indigenous mothers (25% drop) than Indigenous mothers (6% drop).

Indigenous babies

While the focus of this paper is on national data about the birthweight of babies born to Indigenous mothers, data about Indigenous babies are available for 6 jurisdictions for 2011. Of all liveborn Indigenous babies born in 2011 in the 6 jurisdictions, 11.5% were of low birthweight. National data about Indigenous babies will be available from 2012 onwards.