Better health and ageing for all Australians

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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 (foetal 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 is a risk factor for neurological and physical disabilities. Children with extremely low birthweight (less than 1,000 grams) are more likely to have psycho-social problems, difficulties at school, and, when they become teenagers, lower achievement on intellectual measures, particularly arithmetic (AIHW 2011f).

Low birthweight babies may also be more vulnerable to illness throughout childhood and into adulthood. Evidence indicates that low birthweight is associated with an increased risk of Type 2 diabetes and high blood pressure (AIHW 2011f), higher mortality from cardiovascular and renal diseases in adulthood (White et al. 2010a), and from pulmonary causes in both childhood and adulthood (Hoy et al. 2010).

Risk factors include maternal smoking, socioeconomic disadvantage, the weight and age of the mother, the number of babies previously born to the mother, the mother's nutritional status, excessive alcohol consumption, poor antenatal care, illness during pregnancy, multiple births and the duration of pregnancy (see measure 2.21) (SIMC 2004; AMA 2005b; AIHW 2011f; Eades et al. 2008; ABS & AIHW 2008).

Findings:

Top of pageIn the period 2007–09, low birthweight was twice as common among babies born to Aboriginal and Torres Strait Islander mothers as among those with a non-Indigenous mother (12% compared with 6%). For babies born to Aboriginal and Torres Strait Islander mothers, the low birthweight rate increased by 11% between 1991 and 2009, and the gap between low birthweight rates has also increased. However, more recent trends in low birthweight from 2000 to 2009 have found a significant decline in the proportion of babies born to Aboriginal and Torres Strait Islander mothers with low birthweight for both singleton births (7%) and total Indigenous births (6%). In 2009, the mean birthweight for infants born to Aboriginal and Torres Strait Islander mothers was 3,183 grams compared with 3,381 grams for infants born to other Australian mothers.

A multivariate analysis of perinatal data for the period 2006–08 has shown that for Aboriginal and Torres Strait Islander mothers, 33% of all low birthweight births can be attributed to smoking during pregnancy, compared with 13% for other Australian mothers. Smoking during pregnancy accounted for 24% of the gap in low birthweight births between Indigenous and other mothers. A study in Qld found that 76% of Aboriginal and Torres Strait Islander mothers who gave birth to a low birthweight singleton baby at full-term reported smoking during pregnancy (Khalidi et al. 2012).

Overall, maternal age, particularly teenage pregnancy, was not a significant contributor to the total burden of low birthweight among babies with Indigenous mothers (accounting for 1.2%). However, other Australian mothers in the younger age groups were at increased risk of giving birth to a low birthweight baby. These results may reflect the higher smoking rates for other Australian mothers in the under 20 and 20–24 year age groups, whilst Indigenous mothers had consistently high smoking rates for all age groups (see measure 2.21).

Maternal socioeconomic status (being outside the least disadvantaged quintile) did not increase the risk of Aboriginal and Torres Strait Islander mothers giving birth to a low birthweight baby and contributed only 3% to the total Indigenous low birthweight burden. However, this same factor was a larger component of the total burden for other mothers (11%). Other factors, such as state or territory of birth, number of previous births, or remoteness area had no significant impact on low birthweight outcomes for Indigenous mothers.Top of page

International rate comparisons should be treated with caution because of differences in methods used to classify and collect data, and the quality and reliability of data in each country. The low birthweight rate among babies born to American Indian and Alaska Native mothers is approximately 43% higher than those of other Americans; and in New Zealand, rates are 50% higher for babies born to Maori mothers compared with other New Zealand babies. In Canada, the main birthweight problem among Aboriginal peoples is high birthweight (4,000 grams and over), linked with maternal diabetes (Smylie et al. 2010). In 2009, 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:

Recent trends are promising. Analysis of the perinatal data suggests that the largest potential improvements in low birthweight outcomes for Aboriginal and Torres Strait Islander mothers will result from lowering rates of smoking during pregnancy. Approximately 24% of low birthweight among Indigenous mothers could be prevented if the smoking rate for Indigenous mothers during pregnancy was reduced to that of other mothers.

Analysis of the perinatal data shows that an increase in antenatal visits is associated with a decreased likelihood of low birthweight (see measure 3.01). Research also confirms that appropriate antenatal care and a healthy environment for the mother can improve the chances that the baby will have a healthy 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 foetal growth during pregnancy, the reasons for premature delivery are not well understood. In addition to these health service improvements other factors are important such as health promotion and early intervention to support reductions in smoking, improving the nutrition and health of young women, nutrition during pregnancy, educational attainment and support for strong families and communities.

Australian governments are investing in a range of initiatives aimed at improving child and maternal health. In October 2008, COAG agreed to the National Partnership Agreement on Indigenous Early Childhood Development with joint funding of $564 million over six years. This includes Australian Government funding to state and territory governments for sexual health and young parent programs and support for 85 New Directions: Mothers and Babies Services which provide Aboriginal and Torres Strait Islander families with access to antenatal care; practical advice and assistance with parenting; 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 among 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 made an antenatal visit before 13 weeks of pregnancy. States and territories invest heavily in the area of Indigenous early childhood. For example, the Aboriginal Family Birthing Program in SA has improved engagement with antenatal care in the first trimester, assisted in early identification of complications, reduced rates of preterm births, increased breastfeeding rates and reduced rates of caesarean births.Top of page

The Department of Health and Ageing is currently developing new National Evidence-Based Antenatal Care Guidelines on behalf of all Australian governments. The Guidelines are designed to cover the antenatal care of healthy pregnant women, and present recommendations based on the clinical evidence for a wide range of care. Module 1 of the Guidelines covers the first trimester of pregnancy and provides advice on over 20 topic areas including tobacco smoking, alcohol and nutritional supplements. The Guidelines have been developed with input from the Working Group for Aboriginal and Torres Strait Islander Women's Antenatal Care. They will aim to provide culturally appropriate guidance and information for the health needs of Aboriginal and Torres Strait Islander pregnant women and their families.
Figure 12—Low birthweight babies per 100 live births, by Indigenous status of mother, 1991–2009
Figure 12—Low birthweight babies per 100 live births, by Indigenous status of mother, 1991–2009
Source: AIHW analysis of National Perinatal Statistics Unit (NPSU) National Perinatal Data Collection
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Figure 13—Low birthweight babies per 100 live births by maternal age and Indigenous status, 2008–09
Figure 13—Low birthweight babies per 100 live births by maternal age and Indigenous status, 2008–09
Source: AIHW analysis of National Perinatal Statistics Unit (NPSU) National Perinatal Data Collection
Table 3—Low birthweight babies per 100 live births, by Indigenous status of mother and state/territory of residence, 2007-09

Jurisdiction
Babies of
Indigenous
mothers
Babies of
non-Indigenous
mothers
New South Wales
11.5
5.6
Victoria
13.4
6.2
Queensland
10.7
6.0
Western Australia
15.0
5.7
South Australia
13.6
6.2
Tasmania
10.0
6.5
Australian Capital Territory(a)
13.1
5.2
Northern Territory
13.8
5.5
Australia
12.3
5.9
(a)ACT percentages are influenced by small numbers and high proportions of non-ACT residents who gave birth in the ACT
Source: AIHW analysis of National Perinatal Statistics Unit (NPSU) National Perinatal Data Collection
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