












































AUSTRALIAN POPULATION STUDIES 2019 | Volume 3 | Issue 2 | pages 34-36 
 

© Lazzari 2019. Published under the Creative Commons Attribution-NonCommercial licence 3.0 Australia (CC BY-NC 3.0 
AU). Journal website: www.australianpopulationstudies.org 

Socio-economic changes in the 
age-patterns of childbearing in 
Australia 

Ester Lazzari*  Australian National University 

* Corresponding author. Email ester.lazzari@anu.edu.au. Address: School of Demography, 
ANU College of Arts and Social Sciences, The Australian National University, 9 Fellows Road, 
Acton, ACT 2601, Australia 

Paper received 1 August 2019; accepted 17 October 2019; published 18 November 2019 

 

Over the past three decades the median age of mothers in Australia has continued to rise, although 
age-patterns of childbearing vary widely between poorer and wealthier areas. Using data on the 
number of children ever born to women aged 15 years and over sourced from the 2006 and 2016 
censuses, this DemoGraphic examines changes in the timing and quantum of childbearing of 
Australian mothers across different socio-economic statuses. 

In developed countries, fertility has been progressively decreasing at younger ages and increasing at 
older ages, a phenomenon known as postponement (Kohler et al. 2002). Despite the overall shift 
towards later childbearing, significant variation in the median age of mothers can be found across 
different socio-economic groups. There is a vast literature showing that the trend towards postponed 
childbearing primarily occurs among women with high educational attainment (Heck et al. 1997). Not 
only are highly educated women likely to start their families later because of their pursuit of 
education and career (Kaizer et al. 2007), but they also tend to have fewer children due to the 
natural decline in fertility with age (Steiner and Jukic 2016). 

The 2016 Census was used to quantify the number of babies ever born to women aged 15 years and 
over by the Statistical Areal Level 2 (SA2) of usual residence, as defined by the Australian Statistical 
Geography Standard (ASGS) of the ABS. To analyse whether socio-economic circumstances have an 
effect on the timing of childbearing, I used the Index of Relative Socio-economic Advantage and 
Disadvantage (IRSAD) developed by the ABS, which ranks areas in Australia according to a set of 
variables including relative educational and occupational level (ABS 2018). The index is used to group 
the population into five socio-economic statuses: SES1 (most disadvantaged), SES2, SES3, SES4, and 
SES5 (most advantaged). The index is based on census data and assigns summary values of 
socioeconomic conditions to each geographic area. 

Between 2006 and 2016, the average age of all women who gave birth increased from 29.8 to 30.5 
years old (AIHW 2016). Figure 1 displays the changes over the ten year intercensal period in the 
proportion of women with one, two and three children by age and socio-economic status (SES) as 
defined by the 2016 IRSAD index values. Despite a general increase in the median age of Australian 
mothers across parities, a variation by socio-economic status can be observed, with mothers from 
wealthier areas experiencing substantially later ages at first, second and third birth compared to 

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http://www.australianpopulationstudies.org/
mailto:ester.lazzari@anu.edu.au


Australian Population Studies 3 (2) 2019  Lazzari 35 

 

 
Figure 1: Cumulative difference in the proportion of children ever born between 2006 and 2016 by socio-
economic status and parity 

Source: Calculated by the author using data extracted from the 2006 and 2016 censuses using TableBuilder 

women from poorer areas. At the SES5 level, the gap in the proportion of first-time mothers between 
2006 and 2016 was at its greatest at the age of 26 (9.3 per cent). A recuperation trend can be 
observed after age 26, with the proportion of mothers slightly increasing until age 36, when 4.5 per 
cent more women were first-time mothers than in 2006. Similar patterns can be observed at parity 2 
and 3, even though recuperation at parity 3 is rather modest and the proportion of third-time 
mothers never surpasses that of 2006. By contrast, at the SES1 level, the peak of first-time births was 
reached at the age of 22 at parity 1, 25 at parity 2 and 30 at parity 3, showing an anticipation rather 
than a postponement in childbearing compared to the benchmark year. 



36 Lazzari  Australian Population Studies 3 (2) 2019 

 

Socio-economic circumstances seem to have different impacts on the probability of entry into 
motherhood in different periods of life. The trend of childbearing postponement differs across socio-
economic groups and the increase in the age at birth of Australian mothers is driven by women with 
high socio-economic status. Low socio-economic status was associated with entry into motherhood 
at younger ages, while high socio-economic status was associated with childbearing postponement 
and increased fertility at older ages. Interestingly, fertility was lower among the most disadvantaged 
groups, suggesting that socio-economic circumstances affect both timing and quantum of fertility. By 
the end of the reproductive years, there were 2.5 per cent more first-time mothers and 9.2 more 
second-time mothers in the SES5 than in the SES1, while only a slightly higher proportion of women 
in the SES1 gave birth to a third child by the age of 49 (1.8 per cent). The decrease in the total fertility 
rate from 1.87 in 2006 to 1.79 in 2016 (ABS 2017) seems to be driven by women with low socio-
economic status, which despite having their first child relatively young, have fewer children overall 
than women in higher SES groups. Family policies tend to mainly favour working women and, hence, 
it has been argued that women in higher socio-economic statuses account for these observed fertility 
patterns (McDonald and Moyle 2019). 

References 

ABS (2017) Births, Australia, 2016. Catalogue no. 3301.0. Canberra: ABS. 
ABS (2018) Census of Population and Housing: Socio-Economic Indexes for Areas (SEIFA), Australia, 2016. 

Catalogue no. 2033.0.55.001. Canberra: ABS. 
Australian Institute of Health and Welfare (2019) Australia’s Mothers and Babies 2017 - In Brief. Perinatal 

statistics series 35. Canberra: AIHW. 
Heck K, Schoendorf K C, Ventura S J and Kiely J (1997) Delayed Childbearing by Education Level in the 

United States, 1969–1994. Maternal and Child Health Journal 1 (2): 81-88. 
Kaizer R, Dykstra P A and Jansen M D (2007) Pathways into childlessness: evidence of gendered life course 

dynamics. Journal of Biosocial Science 40 (6): 863-878. 
Kohler H-P, Billari F C and Ortega J A (2002) The emergence of lowest-low fertility in Europe during the 

1990s. Population and Development Review 28(4): 641-680. 
McDonald P and Moyle H (2019) In Australia fertility is falling only for low educated women. N-IUSSP. 

http://www.niussp.org/article/in-australia-fertility-is-falling-only-for-low-educated-womenen-
australie-la-fecondite-baisse-uniquement-chez-les-femmes-peu-scolarisees/. Accessed on 4 July 
2019.  

Steiner A Z and Jukic A M Z (2016) Impact of female age and nulligravidity on fecundity in older 
reproductive age cohort. Fertility and Sterility 105(6): 1584-1588. 

 

http://www.niussp.org/article/in-australia-fertility-is-falling-only-for-low-educated-womenen-australie-la-fecondite-baisse-uniquement-chez-les-femmes-peu-scolarisees/
http://www.niussp.org/article/in-australia-fertility-is-falling-only-for-low-educated-womenen-australie-la-fecondite-baisse-uniquement-chez-les-femmes-peu-scolarisees/

