Fewer multiple births after IVF in Australia and New Zealand
Dr. Kirsty Horsey
Progress Educational Trust20 February 2006
A new report by the Australian Institute of Health and Welfare (AIHW) reveals that the number of babies born after fertility treatments such as IVF has almost tripled in the last ten years. An accompanying drop in the numbers of twins and triplets born after assisted conception has lead to fewer premature births, and fewer babies with a low birth weight being born. The report, entitled 'Assisted Reproduction Technology in Australia and New Zealand 2003', shows that mutiple pregnancies after fertility treatment have dropped from 19.4 per cent in 1994 to 18.1 per cent in 2003.
The report shows that overall, 39,720 treatment cycles were attempted in Australia and New Zealand during 2003, which resulted in 7479 liveborn babies - compared to 2801 infants in 1994. The proportion of babies born with a low birthweight was 21.8 per cent, down from 26.4 per cent in 2000. Professor Michael Chapman, spokesman for the AIHW's National Perinatal Statistics Unit at the University of New South Wales, says the drop in multiple pregnancies reflects a decrease in the number of embryos being transferred per treatment cycle. 'In 1994, three or more embryos were transferred in 48.7 per cent of embryo transfer cycles compared with 4.3 per cent of transfer cycles in 2003', he said.
The report also confirms that younger women undergoing fertility treatment have a better chance of success than older women. 'When we look at the ages of women who used their own fresh embryos, women aged 25 to 29 years achieved more successful outcomes, with 35.1 per cent of embryo transfer cycles achieving a live delivery', said Chapman, adding 'women aged 40 to 44 years had a success rate of 9.5 per cent'.
Professor Chapmann said that the increase in success rates was down to improvements in the techniques for transferring embryos. He also said that 'the laboratories are getting closer and closer to mimicking what happens in a woman's body, by trying to replicate the dark, warm, undisturbed environment of the woman's uterus'.
The report also showed that the number of frozen embryos stored in Australia and New Zealand has quadrupled in the last decade, to over 100,000. Chapman said this increase was down to more women becoming pregnant on their first IVF attempt. Although some will be used in future treatment cycles, Chapman says other couples are simply paying storage fees every year to avoid making a decision about their surplus embryos. He suggested 'a more proactive approach', in which clinics would contact couples as more embryos approached the ten year storage limit recommended by the National Health and Medical Research Council.
Reproduced with permission from BioNews, an email and online sources of news, information and comment on assisted reproduction and genetics.