Aboriginal and Torres Strait Islander Health Performance Framework - 2010

1.01 Low birthweight infants

Page last updated: 26 May 2011

Why is it important?:

Low birthweight (new-born babies weighing less than 2,500 grams) is associated with premature birth or sub-optimal intrauterine environments (fetal growth retardation). Low birthweight infants are at a greater risk of dying during the first year of life and are prone to ill health in childhood. Low birthweight babies may also be more vulnerable to illness throughout childhood and into adulthood. There is some evidence that lower birthweights in Aboriginal and Torres Strait Islander peoples are associated with higher mortality from cardiovascular and renal diseases in adulthood (White et al. 2010), and potentially from pulmonary causes in both childhood and adulthood (Hoy & Nicol 2010).

Risk factors include socioeconomic disadvantage, the weight and age of the mother, the number of babies previously born to the mother, the mother’s nutritional status, smoking and other risk behaviours, illness during pregnancy, multiple births and the duration of pregnancy (SIMC 2004; Australian Medical Association 2005; ABS & AIHW 2008; Eades et al. 2008).

Findings:

In the period 2005–07, low birthweight was more than twice as common among babies born to Aboriginal and Torres Strait Islander mothers than other Australian babies (13% compared with 6%). For babies born to Aboriginal and Torres Strait Islander mothers, the low birthweight rate increased by 13% between 1991 and 2008, and the gap has also increased.

Analysis of the 2005–07 national data confirms that Indigenous low birthweight is associated with smoking during pregnancy, pre-term delivery, multiple births, socioeconomic status and other geographical variables. These relationships appear complex and inter-related.

For the non-Indigenous population, it was the younger mothers who had the highest proportion of low birthweight babies (8%). However, for Indigenous mothers, the percentage of low birthweight babies was highest in the 35+ age group (15%). The age cohort of Indigenous mothers with the largest number of births and low birthweight babies was the 20–29 year age group.

There is a strong relationship between smoking, pre-term birth and low birthweight. In 2007, 16% of babies born to Indigenous mothers who smoked during pregnancy had low birthweight compared with 8% for those who did not smoke. For babies of non-Indigenous women the low birthweight rates were 10% where the mother smoked during pregnancy and 5% for non-smokers. Two-thirds (67%) of low birthweight babies born to Indigenous mothers were pre-term and 12% were multiple births.

The proportion of low birthweight babies born to Aboriginal and Torres Strait Islander mothers was highest among mothers living in the most socio-economically disadvantaged areas (13% compared with 9% in the most advantaged). The remoteness of where the mother lives is also a factor, with rates of 14% for those living in very remote areas compared with 11% in inner regional and 13% in major cities. In very remote areas, babies born to Indigenous mothers were almost 3 times as likely to be of low birthweight as babies born to non-Indigenous mothers in these areas.

There is a small degree of variation in the low birthweight rate between states. The low birthweight rate was highest in the Australian Capital Territory and South Australia (around 18% and 16% of births respectively). (The Australian Capital Territory figure should be treated with caution due to small numbers and the provision of maternity services for women with high risk pregnancies from New South Wales.) Rates are lowest in Tasmania and Queensland (around 8% and 11% of live births respectively). In 2007, the mean birthweight for infants born to Aboriginal and Torres Strait Islander mothers was 3,178 grams compared with 3,382 grams for other babies.

International rate comparisons of low birthweight between Indigenous populations in Australia, Canada, New Zealand and the United States should be treated with caution due to the differences in methods used to classify and collect data, and the quality and reliability of data in each country. Low birthweight among babies born to American Indian and Alaskan native mothers is approximately 43% higher than those of White Americans; and in New Zealand, rates are 50% higher for babies born to Maori mothers compared with European New Zealand babies. In Canada, the main birthweight problem amongst Aboriginal peoples is high birthweight (4,000 grams and over), linked with maternal diabetes (Smylie et al. 2010). In 2005–07 the proportion of high birthweight live-born babies born to Indigenous mothers in Australia was 8%. This compared with 12% of babies born of high birthweight to non-Indigenous mothers.

Implications:

Efforts to improve the birthweight of Aboriginal and Torres Strait Islander children have had limited impact nationally since the early 1990s. The issue impacts on Aboriginal and Torres Strait Islander babies in all states and territories.

Appropriate antenatal care and a healthy environment for the mother can improve the chances that the baby will have a healthy birthweight. Some comprehensive mother and child programs for Aboriginal and Torres Strait Islander women in Australia have significantly improved pregnancy outcome measures including lower rates of low birthweight (Herceg 2005). While improvements in health services such as antenatal and acute care for pregnant women are important to reduce the occurrence of pre-term delivery and improve fetal growth during pregnancy, the reasons for premature delivery are not well understood. In addition to health service improvements other factors are important such as reducing the prevalence of smoking, improving the nutrition and growth of girls during their childhood and adolescence, nutrition during pregnancy, educational attainment, and the overall social and economic conditions for Indigenous Australian women and their families.

Maternal and child health is recognised as a key priority by governments across Australia who are implementing a range of programs. In October 2008, COAG signed the National Partnership Agreement on Indigenous Early Childhood Development with joint funding of around $564 million over six years to address the needs of Indigenous children in their early years. The Australian Government’s New Directions: Mothers and Babies provides Aboriginal and Torres Strait Islander children and their mothers with access to antenatal care; standard information about baby care; practical advice and assistance with parenting; monitoring of developmental milestones by a primary health care service; and health checks for children. In addition, one of the aims of Healthy for Life is to improve access to antenatal, postnatal and child health care. This program aims to improve pregnancy, birth and child health outcomes (including birthweight) and reduce the incidence of illness for Aboriginal and Torres Strait Islander babies and children. Data drawn from this program show a decline in the proportion of low birthweight Indigenous babies in the program and an increase in the number and proportion of Indigenous women who attended an antenatal visit before 13 weeks of pregnancy. The Australian Nurse Family Partnership Program is focused on providing sustained home visiting to selected Indigenous communities across Australia and aims to improve pregnancy outcomes and childhood development including improving birthweights, and effect positive life course decisions. States and territories invest heavily in the area of Indigenous early childhood, for example, through their provision of maternal and child health services.

Australian governments are working collaboratively to develop National Evidence-Based Antenatal Care Guidelines, which will provide nationally consistent guidance on optimal care, including culturally appropriate recommendations, for the antenatal period.

Figure 3 – Low birthweight babies per 100 live births, by Indigenous status of mother, Australia 1991–2007


Figure 3 – Low birthweight babies per 100 live births, by Indigenous status of mother, Australia 1991–2007
Source: AIHW analysis of National Perinatal Statistics Unit (NPSU) National Perinatal Data Collection
Text description of figure 3 (PDF 1 KB)

Figure 4 – Live-born low birthweight babies per 100 live births, by Indigenous status of mother and remoteness, 2005–2007


Figure 4 – Live-born low birthweight babies per 100 live births, by Indigenous status of mother and remoteness, 2005–2007
Source: AIHW analysis of National Perinatal Statistics Unit (NPSU) National Perinatal Data Collection
Text description of figure 4

Table 6 – Low birthweight babies per 100 live births, by Indigenous status of mother and state/territory, 1998–2000, 2001–2003, 2003–2005 and 2005–2007

Babies of Indigenous mothers
Babies of non-Indigenous mothers
1998–2000
2001–2003
2003–2005
2005-2007
1998–2000
2001–2003
2003–2005
2005-2007
New South Wales
11.0
12.2
12.0
11.7
5.7
5.8
5.7
5.7
Victoria
13.4
12.7
14.3
12.8
6.2
6.3
6.3
6.3
Queensland
10.8
11.5
11.7
11.2
6.1
6.2
6.3
6.3
Western Australia
13.3
14.5
14.7
15.3
5.8
5.8
6.0
5.9
South Australia
15.7
17.6
17.5
15.7
6.3
6.2
6.4
6.3
Tasmania
n.a.
n.a.
n.a.
8.2
n.a.
n.a.
n.a.
6.3
Australian Capital Territory
16.7
19.1
17.7
18.1
6.8
6.5
7.1
7.1
Northern Territory
12.7
13.3
14.3
13.7
7.2
6.0
6.6
6.1
Australia
12.0
12.9
13.1
12.7
6.0
6.1
6.1
6.1
Source: AIHW analysis of National Perinatal Statistics Unit (NPSU) National Perinatal Data Collection

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