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FEATURE ARTICLE 2: RECENT INCREASES IN AUSTRALIA'S FERTILITY
In Australia, fertility levels vary between areas with different socio-economic conditions, metropolitan and regional areas and among the states and territories. (End note 1) Differences may exist for a variety of reasons, such as culture, social norms, employment, the economy, and socio-economic status. This article examines the recent increase in Australia's TFR with regard to age of mother and socio-economic conditions to provide some insight into changes in fertility in Australia.
Age of mother
Over the past few decades, the decline in Australia's TFR has been closely associated with the tendency for women to have their babies at older ages. The median age of all women who gave birth in 1995 was 29.1 years; by 2005 this had increased to 30.7 years. When women delay childbearing it reduces the length of time in which they can have babies, generally leading to fewer babies than those who started earlier, and an increased level of childlessness.
Changes in the age pattern of fertility between 1995 and 2005 also show a shift to women having fewer babies at younger ages (less than 30 years) and more at older ages (30 years and over) (graph 7.30). Between 1995 and 2001, this transition occurred mostly in the younger age groups, with the fertility declines of women aged less than 30 years on their own acting to reduce the 2001 TFR by around 8% on the 1995 level (assuming no change in other ages). However, minor increases in fertility from the older age groups provided a 3% offset, resulting in an overall 5% decline in the TFR between 1995 (1.82) and 2001 (1.73).
Between 2001 and 2005 the majority of change in the age-specific fertility rates occurred in the older age groups. Increases in the fertility of women aged 30 years and over (assuming no change in other ages) would have had the effect of lifting the 2005 TFR by around 7% on the 2001 level. However, slight declines in fertility of women aged under 30 years would have had the equivalent effect of reducing the TFR by 2%, resulting in an overall TFR increase of 4% between 2001 and 2005 (to 1.81 babies per woman from 1.73 in 2001).
The transition to an older age-specific fertility pattern is also illustrated by the shift in peak fertility from women aged 25-29 years in 1995 (with 122 babies per 1,000 women) to 30-34 years in both 2001 and 2005 (108 and 118 babies per 1,000 women respectively).
The consequence of the shift to an older age-specific fertility pattern is a change in the proportion of TFR that can be attributed to different age groups. In 1995, 43% of the TFR could be attributed to fertility of women aged 30 years and over; by 2001 this proportion had increased to 48% and by 2005 it had further increased to 52%.
Socio-economic status and changes in fertility
The Australian Bureau of Statistics has developed summary measures, or indexes, derived from the 2001 Census of Population and Housing to measure different aspects of socio-economic conditions by geographic areas. One of these indexes (the Index of Relative Socio-economic Advantage/Disadvantage) has been used in this article to investigate the relationship between fertility and socio-economic conditions in different regions of Australia.
Statistical Local Areas (SLAs) within Australia were divided into five groups, each containing around 20% of the population (i.e. quintiles) based on their Index of Relative Socio-economic Advantage/Disadvantage scores. The first quintile includes areas in Australia with the lowest index scores; that is, areas with the lowest proportions of people with high incomes or in skilled occupations, and the highest proportions of people with low incomes, more employees in unskilled occupations, etc. In this article this group has been referred to as being 'least advantaged'.
Conversely, the fifth quintile represents areas with the highest index scores; that is, areas with the highest proportions of people with high incomes or in skilled occupations, and the lowest proportions of people with low incomes and relatively few people in unskilled occupations, etc. This group has been referred to as being 'most advantaged'.
Levels of fertility in both 2001 and 2005 can be seen to vary according to the socio-economic conditions of geographic areas. Areas of most advantage are associated with lower TFRs, that is, areas with higher proportions of people with high incomes or skilled occupations tend to have lower TFRs. However, the difference in TFR between areas of advantage has decreased between 2001 and 2005 due to greater increases in fertility in the most advantaged areas. The TFR for the most advantaged (fifth) quintile increased by 10% between 2001 and 2005, from 1.37 to 1.51 babies per woman (graph 7.31).
Over the same period the fourth quintile's TFR increased by 6% (from 1.66 to 1.75). The combined increase from the fourth and fifth quintiles accounted for 59% of the overall increase in Australia's TFR between 2001 and 2005.
While there were increases in the TFRs of each of the quintiles over the 2001 to 2005 period, the gains were smaller in the least advantaged quintiles. The smallest change occurred in the quintile with the least advantage (up 1%, from 2.02 to 2.05 babies per woman).
The age-specific fertility patterns of the most and least advantaged quintiles in 2001 and 2005 highlight two features: the younger age profile of mothers in the least advantaged areas of Australia; and the increases in fertility of women aged 30 years and over in the most advantaged areas (graph 7.32).
In 2005, the fertility of young women (under 30 years) contributed 62% of the TFR in the least advantaged quintile, but only 27% in the most advantaged quintile. Teenage fertility (women aged 15-19 years) in the least advantaged quintile was over seven times greater than in the most advantaged quintile (29 babies compared with only 4 babies per 1,000 women aged 15-19 years, respectively). For women aged 20-24 years the fertility difference was six-fold (93 and 14 babies per 1,000 women respectively), while among women aged 25-29 years, the least advantaged quintile recorded a fertility rate more than double that of the most advantaged quintile (131 and 57 babies per 1,000 women respectively).
Between 2001 and 2005 there were significant increases in age-specific fertility rates of women aged 30 years and over in the most advantaged quintile. The fertility rate for women in the peak fertility age group of 30-34 years increased from 112 babies per 1,000 women in 2001 to 125 in 2005, while women aged 35-39 years recorded an increase from 66 to 85 babies per 1,000 women over the same period.
1. For information on state/territory, capital city and balance of state fertility trends, see Australian Social Trends, 2007 (4102.0). Fertility rates used in this article were calculated using population estimates based on results of the 2001 Census of Population and Housing, and may differ from more up-to-date rates calculated using population estimates based on 2006 Census results.