The proportion of multiple pregnancies resulting from assisted reproduction technology (ART) has decreased and the number of treatment cycles has increased, says a report released today by the Australian Institute of Health and Welfare (AIHW).
The report, Assisted Reproduction Technology in Australia and New Zealand 2003, shows a 9% increase in the number of treatment cycles between 2002 and 2003.
The report also shows that multiple pregnancies resulting from ART have decreased from 19.4% in 1994 to 18.1% in 2003.
Professor Michael Chapman, spokesman for the AIHW's National Perinatal Statistics Unit located at the University of New South Wales, says the change reflects a decrease in the number of embryos being transferred per cycle.
'In 1994, three or more embryos were transferred in 48.7% of embryo transfer cycles compared with 4.3% of transfer cycles in 2003,' he said.
In the 2003 cohort, success (the delivery of at least one live baby) was achieved in 23.7% of embryo transfer cycles where women used their own fresh embryos, while the figure for women who used their own frozen embryos was 15.2%.
'When we look at the ages of women who used their own fresh embryos, women aged 25-29 years achieved more successful outcomes, with 35.1% of embryo transfer cycles achieving a live delivery, while women aged 40-44 years had a success rate of 9.5%,' Professor Chapman said.
The average age of women undergoing treatment in 2003 was 35.2 years.
The number of babies born following ART treatment increased by 8.6% between 2002 and 2003.
The proportion of babies that were born preterm (fewer than 37 weeks gestation) was 26.6%, which is down from 32.6% in 2000.
Babies born with low birthweight (less than 2,500 grams) made up 21.8% of all babies born in 2003, and this figure is also down from 2000 when 26.4% of all babies were born with low birthweight.
Both pre-term births and low birthweight are commonly associated with multiple pregnancies.