Baby boom slows, but more births to older mothers
A fall in the rate of women giving birth suggests the baby boom may have peaked, according to a report released today by the Australian Institute of Health and Welfare (AIHW).
The report, Australia’s mothers and babies 2008, shows there was a 0.6 percentage point fall in the overall rate of women aged 15 to 44 years giving birth, from 64.9 per 1,000 women in 2007 to 64.4 per 1,000 women in 2008. Of these, an estimated 3.2% of women who gave birth received assisted reproductive technology (ART) treatment.
‘The proportion of older women giving birth has continued to rise over the past 18 years,’ said Associate Professor Elizabeth Sullivan, of the Institute’s National Perinatal Statistics Unit located at the University of New South Wales.
‘The proportion of mothers aged 35 years and over increased from about 11% in 1991 to about 23% in 2008. Mothers aged 40 years and over made up almost 4% of all women giving birth in 2008 compared to 1.4% in 1991.’
The average age of mothers in 2008 was 29.9, up from 27.9 in 1991, and the average age of first-time mothers increased from 25.8 years in 1991 to 28.2 years in 2008.
‘There are a number of factors that contribute to delayed childbearing, including social, educational and economic factors and increased access to assisted reproductive technology,’ Associate Professor Sullivan said.
Indigenous mothers were younger, with an average age of 25.1 years in 2008, compared with 30.1 years for non-Indigenous mothers. The average age of first-time Indigenous mothers was 21.0 years.
For a second year in a row, the rate of caesarean section did not increase, with 31% of women who gave birth doing so by caesarean section. A further 57% had a non-instrumental vaginal birth.
Indigenous mothers had a lower caesarean rate than non-Indigenous mothers (25% compared with 31%). Advancing maternal age was associated with higher rates of caesarean section.
About 11% of mothers had an instrumental (forceps or vacuum extraction) assisted vaginal birth. This rate has remained stable over the last decade.
Instrumental birth was more prevalent in major cities, and a larger proportion of women who had instrumental deliveries were first-time mothers.
The proportion of women who smoked while pregnant was 16%. Over half of Indigenous mothers reported smoking during pregnancy (51%), compared with 14% of non-Indigenous mothers.
Of babies born in 2008, 6.1% of live births were of low birthweight (less than 2,500 grams). This rate of low birthweight was the lowest in the decade 1999–2008.