Births
Information on births is published annually by the ABS from birth registration data and through the National Perinatal Data Collection (Midwives collections) held by the AIHW National Perinatal Statistics Unit (NPSU). The latest available data from the National Perinatal Data Collection are for 2002 and from ABS birth registrations are for 2003. The number of Indigenous births in both data collections is likely to be an underestimate as Indigenous status is not always recorded.
In 2003, there was a total of 11,740 registered births in Australia where at least one parent was of Indigenous origin, accounting for around 5% of total births (ABS 2004a). Of these Indigenous babies, around one-third (31%) had an Indigenous mother and an Indigenous father, and 43% had an Indigenous mother and a non-Indigenous father - a total of 8,567 births (73%) to Indigenous mothers. The remaining 27% of Indigenous babies had non-Indigenous mothers and Indigenous fathers.
In the National Perinatal Data Collection, which collects information on births to Indigenous mothers, there were 8,929 births to Aboriginal and Torres Strait Islander mothers in 2002 (8,827 live births and 102 foetal deaths). This represented 4% of the births where Indigenous status was known (249,266 births) in Australia. The differences between ABS birth registration data and the Perinatal Data Collection are thought to reflect differences in the level of Indigenous identification in the two data collections and delays or failure to register the birth of a child (ABS 2004a).
Gestational age
Gestational age is the length of the pregnancy in completed weeks. The gestational age for term pregnancies is between 37 and 41 weeks; for preterm births it is less than 37 weeks. In 2000-02, 13% of births to Indigenous mothers were preterm. Indigenous mothers had twice the rate of preterm births as non-Indigenous mothers. Almost one in four (24%) preterm births occurred at a gestational age of less than 32 weeks.
Birthweight
Babies born with a birthweight of less than 2,500 grams are classified as ‘low birthweight’. Low birthweight may be a result of preterm birth, foetal growth restriction, a combination of the two, or other factors such as socioeconomic disadvantage, the age of the mother, the number of babies previously born, the mother’s nutritional status, smoking and other risk behaviours, and illness during pregnancy (Horter et al. 1997; Kramer 1998). Low birthweight babies are at greater risk of poor health and death. They may require longer periods of hospitalisation after birth, and are more likely to develop significant disabilities (Leeson et al. 2001; Mick et al. 2002).
6.6 birthweight of live-born babies, by Indigenous status of the mother(a) - 2000-02 |
| |
| | Low birthweight(b) | Normal or high birthweight(c) | Total(d) | Mean birthweight | |
| | no. | % | no. | % | no. | % | grams | |
| |
New South Wales | | | | | | | | |
| Indigenous | 765 | 12.0 | 5 601 | 87.9 | 6 371 | 100.0 | 3 203 | |
| Non-Indigenous | 14 686 | 5.8 | 236 850 | 94.1 | 251 617 | 100.0 | 3 389 | |
Victoria | | | | | | | | |
| Indigenous | 157 | 13.1 | 1 046 | 86.9 | 1 203 | 100.0 | 3 176 | |
| Non-Indigenous | 11 607 | 6.3 | 173 691 | 93.7 | 185 316 | 100.0 | 3 368 | |
Queensland | | | | | | | | |
| Indigenous | 950 | 11.6 | 7 256 | 88.4 | 8 209 | 100.0 | 3 210 | |
| Non-Indigenous | 8 650 | 6.2 | 130 254 | 93.8 | 138 912 | 100.0 | 3 396 | |
South Australia | | | | | | | | |
| Indigenous | 226 | 17.7 | 1 052 | 82.3 | 1 278 | 100.0 | 3 069 | |
| Non-Indigenous | 3 258 | 6.3 | 48 435 | 93.7 | 51 695 | 100.0 | 3 371 | |
Western Australia(e) | | | | | | | | |
| Indigenous | 669 | 14.5 | 3 959 | 85.5 | 4 629 | 100.0 | 3 118 | |
| Non-Indigenous | 4 073 | 5.8 | 65 699 | 94.2 | 69 776 | 100.0 | 3 368 | |
Northern Territory | | | | | | | | |
| Indigenous | 550 | 13.0 | 3 675 | 86.8 | 4 235 | 100.0 | 3 126 | |
| Non-Indigenous | 406 | 6.0 | 6 360 | 93.8 | 6 779 | 100.0 | 3 364 | |
Australian Capital Territory(f) | | | | | | | | |
| Indigenous | 39 | 21.8 | 140 | 78.2 | 179 | 100.0 | 3 037 | |
| Non-Indigenous | 927 | 6.7 | 12 832 | 93.2 | 13 763 | 100.0 | 3 396 | |
Australia(g) | | | | | | | | |
| Indigenous | 3 356 | 12.9 | 22 729 | 87.1 | 26 104 | 100.0 | 3 169 | |
| Non-Indigenous | 43 607 | 6.1 | 674 121 | 93.9 | 717 858 | 100.0 | 3 382 | |
| |
(a) Excludes births to mothers whose Indigenous status was not stated. |
(b) Less than 2,500 grams. |
(c) 2,500 grams or more. |
(d) Includes births where birthweight was not stated. Excludes foetal deaths. |
(e) Data may differ from those published by the department of Health, Government of Western Australia. |
(f) Includes ACT and non-ACT residents who gave birth in the ACT. Among live-born babies of ACT resident Indigenous mothers who gave birth in the ACT, 10.9% weighed less than 2,500 grams. |
(g) Excludes data for Tasmania. |
AIHW, National Perinatal Data Collection. |
In the period 2000-02, babies of Indigenous mothers were twice as likely to be of low birthweight as babies born to non-Indigenous mothers (13% compared to 6%) (table 6.6). Since 1991, there appears to have been little change in both the proportion of low birthweight babies born to Indigenous mothers and their mean birthweight (Plunkett et al. 1996; ABS & AIHW 1999, 2003).
Perinatal mortality
Perinatal deaths include both foetal deaths (stillbirths where birthweight is at least 400 grams or the gestational age is 20 weeks or over) and neonatal deaths (deaths within the first 28 days of life). Perinatal deaths may be underestimated because the number of neonatal deaths may not be accurately recorded, particularly deaths of babies who are transferred, readmitted to hospital, or who die at home. This is because some states and territories do not link records of registered perinatal deaths and the birth records of these babies in the National Perinatal Data Collection (Nassar et al. 2000). In recent years, a number of states and territories have linked their perinatal data collections to the registered perinatal deaths of their respective Registries of Births, Deaths and Marriages, in an effort to improve the extent to which neonatal deaths are recorded. This has led to improved information about perinatal deaths in those states and territories, and the reporting of higher numbers of neonatal deaths. Valid comparisons between the neonatal data and states and territories are therefore not always possible because not all states and territories have linked the two relevant data sets in order to improve the identification of neonatal deaths. In addition, differences in perinatal death rates may, in part, reflect the extent to which regional differences in the identification of babies of Indigenous mothers affect the overall level of identification within each jurisdiction.
For the period 1998-2002, the perinatal mortality rate for babies born to Indigenous women in Queensland, Western Australia, South Australia and the Northern Territory was twice that for babies born to non-Indigenous women in these jurisdictions (table 6.7). Foetal deaths accounted for the highest proportion of perinatal deaths (around 61% of Indigenous perinatal deaths and 68% of non-Indigenous perinatal deaths). In South Australia, the reported perinatal mortality rate for babies born to Indigenous women was three times the rate for babies born to non-Indigenous mothers (26 deaths per 1,000 compared with 9 deaths per 1,000).
6.7 Perinatal mortality, by Indigenous status of the mother - 1998-2002 |
| |
| | Foetal deaths | Neonatal deaths(a) | Total deaths(b) | |
| | no. | rate(c) | no. | rate(c) | no. | rate(c) | |
| |
Indigenous | | | | | | | |
| Queensland | 172 | 12.3 | 108 | 7.8 | 280 | 20.1 | |
| South Australia | 39 | 18.0 | 18 | 8.5 | 57 | 26.3 | |
| Western Australia(d) | 100 | 12.9 | 65 | 8.5 | 165 | 21.2 | |
| Northern Territory(e) | 91 | 13.3 | 66 | 9.8 | 157 | 22.9 | |
| Total | 402 | 13.1 | 257 | 8.4 | 659 | 21.4 | |
Non-Indigenous | | | | | | | |
| Queensland | 1 561 | 6.8 | 831 | 3.6 | 2 392 | 10.3 | |
| South Australia | 545 | 6.2 | 241 | 2.7 | 786 | 8.9 | |
| Western Australia(d) | 790 | 6.7 | 239 | 2.0 | 1 029 | 8.7 | |
| Northern Territory(e) | 74 | 6.5 | 47 | 4.2 | 121 | 10.6 | |
| Total | 2 970 | 6.6 | 1 358 | 3.0 | 4 328 | 9.6 | |
| |
(a) Data may exclude neonatal deaths within 28 days of birth for babies transferred or readmitted to hospital and those dying at home, for some states and territories. |
(b) Excludes deaths of babies born to mothers whose Indigenous status was not stated. |
(c) Per 1,000 perinatal deaths. |
(d) Data may differ from those published by the Department of Health, Government of Western Australia. |
(e) Neonatal deaths data for 2000-02 from Stewart & Li 2005. |
AIHW, National Perinatal Data Collection |