Gestational age

Gestational age is the duration of pregnancy in completed weeks. The gestational age of a baby has important implications for their health, with poorer outcomes generally reported for those born early. Gestational age is reported in 3 categories: pre-term (less than 37 weeks gestation), term (37 to 41 weeks) and post-term (42 weeks and over).

The vast majority of babies (9 in 10) in Australia are born at term (37–41 weeks). This is similar across the states and territories and has been stable over time.

Babies born to mothers who smoked at any point during pregnancy were more likely to be born pre-term (1 in 7 babies) than babies born to mothers who had not smoked (1 in 12 babies).

Singleton babies were more likely to be born at term, while twins and babies of other multiple births were more likely to be born pre-term.