Births and pregnancy outcome

Births and pregnancy outcome

In 2011, there were 17,621 births registered in Australia with one or both parents identified as Indigenous (6% of all births registered) [1]. This figure probably underestimates the true number slightly as Indigenous status is not always identified, and there may be a lag in birth registrations. The ABS estimates that 96% of Indigenous births in 2002-2006 were correctly identified as such [2]. Completeness of identification varied across the country, with only Vic, Qld, WA, SA and the NT having levels above 90%.

In 2011, both parents identified as Indigenous in 31% of Indigenous registered births [1]. Only the mother identified as Indigenous in 42% of Indigenous registered births (including births where paternity was not acknowledged and those where the father's Indigenous status was unknown), and only the father identified as Indigenous in 27% (including births where the mother's Indigenous status was unknown).

Age of mothers

In 2011, Indigenous women had more babies and had them at younger ages than did non-Indigenous women – teenagers had one-fifth (19%) of the babies born to Indigenous women, compared with only 3.8% of those born to all mothers [1]. The median age of Indigenous mothers was 24.8 years, compared with 30.6 years for all mothers. 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 all women (Table 2). The fertility rate of teenage Indigenous women (78 babies per 1,000 women) was almost five times that of all teenage women (16 babies per 1,000).

Table 2: Age-specific fertility rates, by Indigenous status of mother, selected jurisdictions, Australia, 2011

Status of mother/age-group (years)	Jurisdiction
	NSW	Vic	Qld	WA	SA	NT	Australia
Source: ABS, 2012 [1]
Notes: Rates per 1,000 women in each age-group n.p. refers to numbers not available for publication, but included in totals where applicable Figures are not provided for Tas and the ACT because of the small numbers involved and doubts about the level of identification of Indigenous births, but numbers for those jurisdictions are included in figures for Australia
Indigenous mothers
15-19	71	54	85	106	72	80	78
20-24	157	117	163	180	153	145	155
25-29	162	128	155	154	147	115	147
30-34	117	111	112	101	103	79	105
35-39	54	64	58	52	38	36	52
40-44	11	n.p.	13	n.p.	10	10	11
All mothers
15-19	14	9	22	19	15	44	16
20-24	51	37	66	58	51	98	52
25-29	101	90	111	107	105	105	101
30-34	125	123	117	125	121	104	122
35-39	73	74	64	66	62	58	70
40-44	16	16	13	15	13	n.p.	15

Total fertility rates

In 2011, total fertility rates were 2,740 births per 1,000 for Indigenous women and 1,884 per 1,000 for all women (Table 3) [1]. The highest total fertility rate for Indigenous women was for WA (3,011 babies per 1,000 women), followed by Qld (2,932 per 1,000) and NSW (2,863 per 1,000).

Table 3: Total fertility rates, by Indigenous status of mother, selected jurisdictions, Australia, 2011

Status of mother	Jurisdiction
	NSW	Vic	Qld	WA	SA	NT	Australia
Source: ABS, 2011 [1]
Notes: Total fertility rate is the number of children born to 1,000 women at the current level and age pattern of fertility Figures are not provided for Tas and the ACT because of the small numbers involved and doubts about the level of identification of Indigenous births. Numbers for those jurisdictions are included in figures for Australia
Indigenous	2,863	2,486	2,932	3,011	2,611	2,323	2,740
All mothers	1,908	1,748	1,964	1,953	1,847	2,131	1,884

Birthweights

The average birthweight of babies born to Indigenous mothers in 2010 was 3,190 grams, almost 190 grams less than the average for babies born to non-Indigenous mothers (3,376 grams) [3]. Babies born to Indigenous women in 2010 were twice as likely to be of low birthweight (LBW) (12.0%) than were those born non-Indigenous women (6.0%). (LBW, defined as a birthweight of less than 2,500 grams, increases the risk of death in infancy and other health problems.)

The LBW proportions for babies born to Indigenous women were highest in SA (16.0%), the NT (13.8%), and WA (13.6%). LBW proportions were higher for Indigenous mothers than for all mothers in all jurisdictions (Table 4) [3].

Table 4: Mean birthweights and percentage of low birthweight for babies born to Indigenous and all mothers, selected jurisdictions, Australia, 2010

	NSW	Vic	Qld	WA	SA	NT	Australia
Source: Li, Zeki, Hilder, and Sullivan, 2012 [3]
Notes: LBW is defined as less than 2,500 grams
Indigenous mothers
Mean birthweight	3,233	3,234	3,199	3,139	3,130	3,119	3,190
% low birthweight	10.7	10.3	11.5	13.6	16.0	13.8	12.0
All mothers
Mean birthweight	3,376	3,366	3,382	3,353	3,344	3,292	3,369
% low birthweight	5.8	6.3	6.4	6.1	6.8	8.8	6.2

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 duration of the pregnancy [4]. A mother's alcohol consumption and use of tobacco and other drugs during pregnancy 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) [5]. The comparable figures for live babies born to non-Indigenous women were 3,210 for women who smoked and 3,416 grams, for women who did not smoke. The impact of tobacco smoking during pregnancy can also be seen also in the proportions of LBW liveborn babies; in 2007 the proportion of LBW babies was twice as high among Indigenous mothers who smoked during pregnancy (16%) as among Indigenous mothers who did not smoke during pregnancy (8.2%) [6]. Similarly, 10% of babies born to non-Indigenous mothers who smoked were of LBW, compared with 5.0% of those whose non-Indigenous mothers did not smoke. In 2009, half (50%) of Indigenous mothers and 13% of non-Indigenous mothers reported smoking during pregnancy [7].

The 2000-2001 Western Australian Aboriginal Child Health Survey (WAACHS) reported slightly higher average birthweights than the weights documented above – 3,110 grams for babies born to Indigenous mothers who used tobacco in pregnancy and 3,310 grams for those whose Indigenous mothers did not [8]. The lowest average birthweights reported in the WAACHS were for babies whose Indigenous mothers used marijuana with tobacco (3,000 grams) or marijuana with both tobacco and alcohol (2,940 grams).

References

1. Australian Bureau of Statistics (2012) Births, Australia, 2011. Canberra: Australian Bureau of Statistics
2. Australian Bureau of Statistics (2007) Births, Australia, 2006. Canberra: Australian Bureau of Statistics
3. Li Z, Zeki R, Hilder L, Sullivan EA (2012) Australia's mothers and babies 2010. Canberra: Australian Institute of Health and Welfare
4. Ashdown-Lambert JR (2005) A review of low birth weight: predictors, precursors and morbidity outcomes. Journal of the Royal Society for the Promotion of Health; 125(2): 76-83
5. Leeds K, Gourley M, Laws P, Zhang J, Al-Yaman F, Sullivan EA (2007) Indigenous mothers and their babies, Australia 2001-2004. Canberra: Australian Institute of Health and Welfare
6. Australian Institute of Health and Welfare (2011) Aboriginal and Torres Strait Islander health performance framework 2010: detailed analyses. Canberra: Australian Institute of Health and Welfare
7. Li Z, McNally L, Hilder L, Sullivan EA (2011) Australia's mothers and babies 2009. Canberra: Australian Institute of Health and Welfare
8. Zubrick SR, Lawrence DM, Silburn SR, Blair E, Milroy H, Wilkes T, Eades S, D'Antoine H, Read AW, Ishiguchi P, Doyle S (2004) The health of Aboriginal children and young people. Perth: Telethon Institute for Child Health Research

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