Assisted reproductive technologies (ART) — such as in vitro fertilisation (IVF) — are a group of procedures used to assist women to become pregnant. ART usually involves removing oocytes (eggs) from a woman's ovaries, fertilising them in the laboratory and then transferring the resulting embryo(s) back into a woman's uterus. Over the last five years, the number of ART procedures has increased by over 10% per year on average in Australia and New Zealand. ART children now account for an estimated 3.3% and 2.0% of children born in Australia and New Zealand respectively.
This is the fourteenth annual report on the use of ART in Australia and New Zealand, and presents data on women who underwent ART treatments in 2008, and the resulting pregnancies and baby outcomes.
Increased use of ART treatments
There were 61,929 ART treatment cycles reported in Australia and New Zealand in 2008, a 9.0% increase on 2007 and a 47.8% increase on 2004. Of the cycles undertaken in 2008, 91.9% were from Australian fertility centres and 8.1% were from New Zealand fertility centres. Women used their own oocytes/embryos in about 95%of treatments, and over 36% of all cycles used frozen/thawed embryos.
Shift in practice to blastocyst culture
The use of blastocyst culture accounted for 38.6% of embryo transfer cycles in 2008, which is significantly higher than the percentage of cycles transferring blastocysts in 2004 (17.1%).
Women's age and parity
Almost one quarter (23.3%) of cycles were in women who had previously given birth. The average age of women undergoing ART treatment using their own oocytes was 35.7 years, slightly older than the average age (35.5 years) in 2007. One in four (26.6%) autologous fresh cycles undertaken in 2008 were in woman aged 40 years or older. The average age of women undergoing ART treatment using donor oocytes/embryos was 41 years.
Treatment outcomes and number of babies
Of the 61,929 treatment cycles, 22.6% resulted in a clinical pregnancy, and 17.2% resulted in a live delivery (the birth of at least one liveborn baby). There were 10,633 live deliveries resulting in 11,528 liveborn babies.
A clear trend in ART treatment over the last five years has been the reduction in the rate of multiple birth deliveries. The multiple delivery rate for ART treatment cycles undertaken in 2008 was 8.4% – compared to 10.0% in 2007 and 16.4% in 2004. This reduction is due to a voluntary shift in practice by clinicians and patients to single embryo transfer (SET), with the proportion of SET cycles increasing from 40.5% in 2004 to 67.8% in 2008. Importantly, this substantial decrease in the multiple delivery rate has been achieved while clinical pregnancy rates have remained stable at around 22% per cycle.