Australia's mothers and babies

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)
• post-term (42 weeks and over).

Over time, the proportion of babies born:

• between 20 and 36 weeks has remained steady between 2010 (8.3%) and 2023 (8.4%), with a peak of 8.7% reached most recently in 2018
• between 37 and 39 weeks has increased (babies born at 39 weeks increased from 26% in 2010 to 33% in 2023)
• from 40 weeks onwards has decreased (babies born at 40 weeks decreased from 26% in 2010 to 19% in 2023). 

Figure 1 presents data on the grouped gestational age of pre-term and post-term babies and the individual completed weeks for term babies, for 2010 and 2023.

Figure 2 presents trend data on the gestational age of babies, by selected maternal and baby characteristics, between 2010 (or earliest available year of data) and 2023. Select the ‘Current data’ button to view 2023 data.

Figure 2: Proportion of babies, by gestational age group and selected topic

In 2023, most babies (91%) in Australia were born at term (37–41 weeks), with 31% born at early term (37 or 38 weeks) and 60% at full term (39–41 weeks).

Less than 1 in 10 babies (8.4%) were born pre-term, and of these the majority were born between 32 and 36 completed weeks.

Babies born to mothers who reported smoking at any time during pregnancy were more likely to be born pre-term (14%) than babies born to mothers who had not reported smoking (7.8%).