Australia continues to be one of the safest countries globally for IVF treatment, the latest data shows.
Fewer and fewer twins and triplets are being born through IVF in Australia, bringing IVF and overall Australian multiple birth rates closer together, a new report by UNSW Sydney medical researchers shows.
Having twins and triplets was once considered the greatest risk of IVF treatment, but the latest IVF report shows that multiple births are less and less common. And the decrease in multiple birth rates – resulting from an accompanying increase in single embryo transfers – reflects the level of safety parents-to-be can expect when pursuing Assisted Reproductive Technology (ART) in Australia and New Zealand, the researchers say.
The 2022 Australian and New Zealand Assisted Reproduction Database (ANZARD) report – the most recent year for which complete IVF data is available – found the multiple birth rate following ART decreased from 3.2% in 2018 to 2.7% in 2022 – a record low in Australia and New Zealand's 45-year IVF history.
The rate of single embryo transfers, which is the main factor behind the low multiple birth rate, continued to increase from 90.6% in 2018 to 94.2% in 2022.
"Our multiple birth rate is among the lowest in the world, and has been achieved at the same time as pregnancy rates have been improving," says Professor Georgina Chambers, lead author of the report and Director of the National Perinatal Epidemiology and Statistics Unit at UNSW Medicine & Health.
"IVF multiple birth rates are decreasing around the world, but Australia has been one of the countries that has led the way in demonstrating that world-class success rates can be achieved by transferring one embryo at a time. Indeed, Australia and New Zealand have had IVF multiple birth rates of less than 5% for a decade, while the average multiple birth rate for European countries remains at 10.2%," says Prof. Chambers.
"This low rate is primarily the result of single embryo transfers. For example, the average single embryo transfer rate in Europe is around 54%, which is why they see higher multiple birth rates, so overall Australia really is a leader in IVF safety."
Petra Wale, a senior embryologist and President of the Fertility Society of Australia and New Zealand (FSANZ), which funded the report, says: "The rise in single embryo transfers has been crucial in ensuring that most babies born through IVF are healthy, full-term singletons. This practice not only enhances the babies' wellbeing but also supports maternal health."
Multiple pregnancies and births bring with them increased risk of certain conditions, including preeclampsia, gestational diabetes, post-partum haemorrhage, pre-term birth, and low birthweight.
"The continuous improvement in ART practices in Australia and New Zealand not only supports the health and safety of mothers and babies but also demonstrates our commitment to providing the highest standard of reproductive care," Dr Wale says.
High success rates alongside safety
There were 108,913 ART treatment cycles performed in Australian and New Zealand ART Units in 2022 (100,039 and 8874 respectively), resulting in the birth of 20,058 babies.
More than one in three (38.9%) of the 37,810 women who started their first ART cycle between January 2019 and December 2020 and were followed until December 2022 achieved a live birth in their first complete ART cycle, and 59.5% achieved a live birth by their sixth complete ART cycle.
"It's encouraging to see these rates – they show that we are able to maintain a high level of safety in Australia and New Zealand while also keeping success rates high," Prof. Chambers says.
"These findings underscore the commitment to patient safety and success, benefiting both intended parents and the broader community," says Dr Wale.
Embryos transferred during ART can either originate from the cycle in which they were created (fresh cycle) or be frozen (cryopreserved) and thawed before transfer (thaw cycle).
Dr Simon McDowell, a New Zealand-based fertility specialist and the vice-president of the FSANZ, says: "This improvement is attributed to better synchronization between the embryo's development stage and the optimal condition of the endometrium during thawed embryo transfer cycles. Unlike fresh transfers, where hormonal stimulation can disrupt the uterine environment, thawed embryos are transferred in a subsequent cycle, ensuring that the endometrium is perfectly primed for implantation. Additionally, the absence of the ovarian stimulation effects seen in fresh cycles allows for a more favourable hormonal environment, further enhancing the chances of a successful pregnancy."
Maternal age is one of the key factors associated with success: the cumulative live birth rate following three ART cycles was 70.4% for women aged under 30 compared to 22.5% for women aged 40–44 and 1.3% for women aged 45 or older.
"While female age is a key factor in IVF success, a woman is not a statistic and there are many other factors that play a role in success," says Prof. Chambers.
"This is where the YourIVFSuccess Patient Estimator can help patients – it uses information on over 800,000 IVF cycles performed in Australia to calculate a patient's individualised chance of IVF success, based on the information they enter online about their personal circumstances and treatment characteristics."
Egg freezing increasing yet again
In 2022, the researchers reported 6899 fertility preservation cycles, an 89% increase from 2020. These cycles involve freezing all suitable eggs or embryos for potential future use.
For the third time, ART units reported people's reasons for freezing eggs to ANZARD, with 626 cycles – just under 10% – of egg freezing cycles reported as due to someone's cancer diagnosis.
"More and more women are choosing to freeze their eggs to extend their fertility, but it is important that patients understand that even if they freeze their eggs, it doesn't guarantee IVF success in the future," says Prof. McDowell.
The ANZARD report contains data from all 98 IVF clinics operating in Australia and New Zealand. It presents information about IVF cycles undertaken in 2022 and the resulting babies born in 2022 and 2023. The data presented in the report is managed by the National Perinatal Epidemiology and Statistics Unit (NPESU) within UNSW's Centre for Big Data Research in Health and the School of Clinical Medicine.
Key stats from the 2022 report
- 108,913 ART treatment and lab-only cycles were performed in Australian and New Zealand ART Units in 2022 (100,039 and 8874, respectively), representing a slight overall decrease of 2.1% from 2021.
- Of the 108,913 initiated ART cycles, 20,058 babies were born, including 19,833 liveborn babies.
- Over a third (38.9%) of women who commenced ART in 2019/2020 achieved a live birth in their first ART cycle. After six complete ART cycles, women had a 59.5% chance of achieving a live birth.
- Of all autologous and recipient cycles, 12.8% were undertaken by single female and 4.2% by female-female intending parents.
- The proportion of births that were twins or triplets was 2.7%.
- Women used their own eggs or embryos in nearly 94% of cycles in 2022; 57.6% were fresh cycles, and 36.1% were thaw cycles.
- There were 6899 fertility preservation cycles performed in 2022, representing an increase of 89% from 2020.
