IVF birth rates for twins and triplets fall to record low

Rates of twins and triplets amongst babies born in Australia as a result of IVF have fallen to record lows, according to a new report by researchers from University of NSW.
The report looked at the rates of Assisted Reproductive Technology (ART) in Australia and New Zealand in 2022 — the most recently available data.
It found there were 19,833 live births as a result of ART in 2022, of which twins or triplets made up just 2.7 per cent.
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The rate of single embryo transfers was the main factor behind low multiple birth rates and is important because multiple pregnancies are linked with poorer outcomes for both mothers and babies.
Multiple births were once common place in IVF treatment as specialists transferred multiple embryos to increase the chances of pregnancy.
But multiple pregnancies and births are linked to an increased risk of conditions such as preeclampsia, gestational diabetes, post-partum haemorrhage, pre-term birth and low birthweight.
The 2022 Australian and New Zealand Assisted Reproduction Database (ANZARD) report examined data from all 98 IVF clinics in Australia and New Zealand and found multiple births from ART decreased from 3.2 per cent in 2018 to 2.7 per cent in 2022.
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This was a record low in Australia and New Zealand’s 45-year IVF history and means we now have one of the lowest IVF multiple birth rates in the world.
This was largely because the rate of single embryo transfers has increased in that time from 90.6 per cent in 2018 to 94.2 per cent in 2022.
Professor Georgina Chambers is the director of the National Perinatal Epidemiology and Statistics Unit at UNSW Medicine & Health and lead author of the report.
She said Australia’s multiple birth rate was amongst the lowest in the world at the same time IVF pregnancy rates were improving.
“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,” she said.
“Indeed, Australia and New Zealand have had IVF multiple birth rates of less than 5 per cent for a decade, while the average multiple birth rate for European countries remains at 10.2 per cent.”
The Fertility Society of Australia and New Zealand (FSANZ) president and senior embryologist Petra Wale said single embryo transfers enhanced the well-being of both mothers and babies.
There were a total of 108,913 ART treatment cycles performed in Australia and New Zealand in 2022, of which 100,039 were in Australia.
This resulted in the birth of 20,058 babies in 2022.
More than one-third of the 37,810 women who started IVF between January 2019 and December 2020 achieved a live birth in their first complete cycle, while 59.5 per cent achieved a live birth by their sixth cycle.
Thaw cycles, which use previously frozen embryos, had higher success rates than fresh cycles.
Live birth rates climbed for both methods, with fresh embryo transfer cycles increasing from 24.6 per cent to 25.9 per cent, while embryo transfers using thawed embryos increased from 29.3 per cent to 32.1 per cent.
Maternal age remains one of the key factors for success.
The overall live birth rate from three ART cycles was 70.4 per cent for women under the age of 30 compared with 22.5 per cent for women aged 40 to 44.
This dropped to just 1.3 per cent for women aged 45 and 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,” Professor Chambers said.
Egg freezing rates are also up, with 6899 fertility preservation cycles in 2022 — an 89 per cent increase since 2020.
Assisted reproductive technology (ART) is a group of procedures that involves using eggs and sperm to create embryos outside the body.
Each ART treatment involves a number of stages or treatment cycles.