Frozen embryo transfer becomes central to IVF in Australia and New Zealand

IVF.net Newsdesk

15 September 2026

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Frozen embryo transfer now accounts for almost three in four ART live births in Australia and New Zealand. The 2024 Australian and New Zealand Assisted Reproduction Database report records 74% of live births following thaw cycles, compared with 65.3% in 2020. Cryopreservation has become central to how treatment is delivered.

UNSW’s accompanying news article describes how improvements in embryo vitrification have supported this transition. Separating embryo transfer from ovarian stimulation gives clinicians flexibility to allow recovery and plan a later transfer. It also allows treatment planning to extend beyond the immediate attempt, including the potential use of stored embryos to build a family over time.

The report shows that 69.1% of embryo transfers involved cryopreserved embryos in 2024. Meanwhile, 44.5% of initiated fresh cycles involved freezing all oocytes or embryos, up from 31.6% in 2020. These figures describe different stages of treatment: a fresh cycle can produce embryos for storage without proceeding to a fresh transfer.

Across 2020 to 2024, live birth rates per transfer increased from 31.2% to 33.3% for frozen embryos and from 25.4% to 26.2% for fresh embryos. These registry comparisons do not establish that freezing improves an individual patient’s outcome. They describe outcomes among the patients and embryos reaching each type of transfer, rather than a randomised comparison of treatment strategies.

Single embryo transfer also became more common, reaching 95.4% in 2024, while the multiple birth rate remained at 2.2%. As the UNSW article highlights, this approach helps reduce risks associated with multiple pregnancies while supporting treatment success.

The findings also reinforce the importance of evaluating IVF over a complete course of treatment. Among 43,849 women starting treatment in 2021 or 2022, 37.4% achieved a live birth from their first complete cycle, defined as one stimulation and its associated fresh and frozen transfers. By six complete cycles, the observed cumulative proportion was 57.6%.

The higher estimate of 76.9% assumes that women who discontinued had the same likelihood of success as those who continued. That assumption matters when communicating prognosis.

For laboratories and clinicians, the broader implication is that retrieval, embryo culture, cryopreservation and subsequent transfers need to be understood together. A transfer-level success rate is useful, but it cannot alone describe the outcome of the treatment pathway that produced it.

Sources

8 August 2026. University of New South Wales