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 on average by over 10% per year in Australia and New Zealand. Latest estimates indicate that 3.1% and 1.8% of babies born in Australia and New Zealand respectively are as a result of ART treatment.
This is the thirteenth annual report on the use of ART in Australia and New Zealand, and presents data on women who underwent ART treatments in 2007, and the resulting pregnancies and baby outcomes.
Increased use of ART treatments
There were 56,817 ART treatment cycles reported in Australia and New Zealand in 2007. This represents a 12.5% increase in the number of cycles undertaken in 2006 and a 53.7% increase in the number of cycles undertaken in 2003. Of the 56,817 cycles, 22.6% resulted in a clinical pregnancy and 17.4% resulted in a live delivery (the birth of at least one liveborn baby). There were 10,856 liveborn babies born following ART treatment in 2007.
In 2007, 92.0% of cycles were from Australian fertility centres and 8.0% were from New Zealand fertility centres. Women used their own oocytes in about 95% of cycles, and over 38% of all cycles used frozen/thawed embryos.
Shift in practice to blastocyst culture
The use of blastocyst culture accounted for 30.6% of embryo transfer cycles in 2007, which is significantly higher than the percentage of cycles transferring blastocysts in 2003 (13.4%).
Women’s age and parity
Almost one quarter (23.6%) of cycles were in women who had previously given birth. The average age of women undergoing ART treatment using their own oocytes was 35.5 years, slightly older than the average age (35.0 years) in 2003. In 2007, one in four (24.2%) fresh cycles in which women used their own oocytes were in woman aged 40 years or older. The average age of women undergoing ART treatment using donor oocytes/embryos was 40.5 years.
Better outcomes for mothers and babies
The most important 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 2007 was 10.0% – compared to 12.0% in 2006, and 18.7% in 2003. 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 32.0% in 2003 to 63.7% in 2007. Importantly, this substantial decrease in the multiple delivery rate has been achieved while clinical pregnancy rates have remained stable around 22% per cycle.