Births and pregnancy outcome
In 2006, there were 12,496 births registered in Australia with one or both parents identified as Indigenous (4.7% of all births registered), but this figure probably underestimates the true number slightly as it has been estimated that only 96% of Indigenous births in 2002-2006 were correctly identified as such [1]. Completeness of identification varies across the country, with only Queensland, Victoria, WA, SA and the NT having levels above 90%.
Both parents were identified as Indigenous in 30% of these births occurring in 2006, only the mother in 41% (including births where paternity was not acknowledged and those where the father’s Indigenous status was unknown), and only the father in 29% [1].
Age of mothers
In 2006, Indigenous women tended to have more babies and to have them at younger ages than did non-Indigenous women – teenagers had more than one-fifth of the babies born to Indigenous women, compared with only 3.6% of those born to non-Indigenous mothers [1]. The median age of Indigenous mothers was 24.6 years, compared with 30.8 years for all women. The highest birth rates (known technically as fertility rates) were for the 20-24 years age group for Indigenous women and in the 30-34 years age group for non-Indigenous women (Table 1). Fertility of teenage Indigenous women (69 babies per 1,000 women) was more than four times the fertility rate for all teenage women (15 babies per 1,000).
Table 1 Age-specific fertility rates, by Indigenous status of mother, selected jurisdictions, Australia, 2006
| Status of mother / age group | Jurisdiction
|
||||||
| NSW | Vic | Qld | WA | SA | NT | Aust | |
| Indigenous | |||||||
| 15-19 | 59 | 52 | 61 | 82 | 78 | 113 | 69 |
| 20-24 | 114 | 107 | 118 | 139 | 151 | 142 | 125 |
| 25-29 | 106 | 99 | 109 | 119 | 134 | 110 | 110 |
| 30-34 | 73 | 87 | 77 | 76 | 96 | 80 | 77 |
| 35-39 | 37 | 28 | 34 | 35 | 43 | 30 | 34 |
| 40-44 | 8 | 8 | 8 | 5 | 6 | 8 | 7 |
| All mothers | |||||||
| 15-19 | 13 | 10 | 20 | 20 | 17 | 64 | 15 |
| 20-24 | 50 | 39 | 61 | 60 | 54 | 98 | 52 |
| 25-29 | 100 | 91 | 107 | 109 | 105 | 106 | 101 |
| 30-34 | 120 | 127 | 112 | 123 | 114 | 103 | 120 |
| 35-39 | 65 | 70 | 55 | 64 | 58 | 55 | 63 |
| 40-44 | 12 | 13 | 9 | 11 | 9 | 11 | 11 |
Source: ABS, 2007 [1]
Notes:
1 Rates per 1,000 women in each age group
2 Figures in this table are restricted to those jurisdictions with estimated identification of Indigenous births of around 90% or higher
Total fertility rates
In 2006, total fertility rates were 2,118 births per 1,000 Indigenous women and 1,814 per 1,000 for all mothers (Table 2) [1]. The highest Indigenous total fertility rate for Indigenous women was for the SA (2,539), followed by the NT (2,412 babies per 1,000) and Western Australia (2,278 babies per 1,000).
Table 2 Total fertility rates, by Indigenous status of mother, selected jurisdictions, Australia, 2006
| Status of mother | Jurisdiction | ||||||
| NSW | Vic | Qld | WA | SA | NT | Aust | |
| Indigenous | 1,984 | 1,898 | 2,044 | 2,278 | 2,539 | 2,412 | 2,118 |
| All mothers | 1,800 | 1,745 | 1,831 | 1,941 | 1,788 | 2,187 | 1,814 |
Source: ABS, 2007 [1]
Notes:
1 Total fertility rate is the number of children born to 1,000 women
at the current level and age pattern of fertility
2 Figures in this table are restricted to those jurisdictions with estimated identification of Indigenous births of around 90% or higher
Birthweights
The average birthweight of babies born to Indigenous mothers in 2005 was 3,158 grams – more than 200 grams less than the average for babies born to non-Indigenous mothers, 3,375 grams (Table 3) [Derived from 2]. Babies born to Indigenous women in 2005 were more than twice as likely to be of low birthweight (LBW) (13.2%) than were those born to non-Indigenous women (6.1%). (LBW, defined as a birthweight of less than 2,500 grams, increases the risk of death in infancy and other health problems.) The low-birthweight proportions for babies born to Indigenous women were highest for SA (17.7%), WA (15.5%) and the NT (14.5%).
Table 3 Mean birthweights and percentage of low birthweight for babies born to Indigenous and non-Indigenous mothers, selected jurisdictions, Australia, 2005
| NSW | Vic | Qld | WA | SA | NT | Aust | |
| Indigenous mothers | |||||||
| Mean birthweight | 3,214 | 3,179 | 3,184 | 3,080 | 3,059 | 3,157 | 3,158 |
| % low birthweight | 12.0 | 13.6 | 11.8 | 15.5 | 17.7 | 14.5 | 13.2 |
| Non-Indigenous mothers | |||||||
| Mean birthweight | 3,382 | 3,369 | 3,385 | 3,359 | 3,361 | 3,338 | 3,375 |
| % low birthweight | 5.7 | 6.3 | 6.3 | 6.0 | 6.0 | 6.7 | 6.1 |
Source: Derived from Laws, Abeywardana, Walker and Sullivan, 2007 [2]
Notes:
- Low birthweight is defined as less than 2,500 grams
- Mean birthweights for babies born to non-Indigenous mothers have been estimated from published figures for Indigenous and all mothers
Risk factors for LBW include socioeconomic disadvantage, the size and age of the mother, the number of babies previously born, the mother’s nutritional status, illness during pregnancy and the duration of the pregnancy [3]. A mother’s alcohol consumption and use of tobacco and other drugs during pregnancy can also impact on the size of her baby.
Tobacco, in particular, has a major impact on birthweight. The mean birthweight of live babies born in 2001-2004 to Indigenous women who smoked was 3,037 grams, more than 250 grams lighter than those born to Indigenous women who did not smoke (3,290 grams) [4]. The comparable figures for live babies born to non-Indigenous women were 3,210 and 3,416 grams respectively. The impact of tobacco smoking during pregnancy was seen also in the proportions of low birthweight liveborn babies – 16% and 10% respectively for Indigenous and non-Indigenous women who smoked during pregnancy, and 10% and 5% for those who didn’t.
The 2000-2001 Western Australian Aboriginal Child Health Survey (WAACHS) reported slightly higher average birthweights – 3,100 grams for babies born to mothers who used tobacco in pregnancy and 3,310 grams for those whose mothers did not [5]. The lowest average birthweights reported in the WAACHS were for babies whose mothers used marijuana with tobacco (3,000 grams) or marijuana with both tobacco and alcohol (2,940 grams).
References
1 Australian Bureau of Statistics (2007) Births Australia, 2006. (ABS catalogue no. 3301.0) Canberra: Australian Bureau of Statistics
2 Laws P, Abeywardana S, Walker J, Sullivan EA (2007) Australia's mothers and babies 2005. (AIHW catalogue no. PER 40) Canberra: National Perinatal Statistics Unit, Australian Institute of Health and Welfare
3 Australian Institute of Health and Welfare (2004) Australia's health 2004: the ninth biennial report of the Australian Institute of Health and Welfare. Canberra: Australian Institute of Health and Welfare
4 Leeds K, Gourley M, Laws P, Zhang J, Al-Yaman F, et al. (2007) Indigenous mothers and their babies, Australia 2001-2004. (AIHW catalogue no. PER 38) Canberra: Australian Institute of Health and Welfare
5 Zubrick SR, Lawrence DM, Silburn SR, Blair E, Milroy H, et al. (2004) The Western Australian Aboriginal Child Health Survey: the health of Aboriginal children and young people. Perth: Telethon Institute for Child Health Research
