Frozen Embryo Transfer Success Rates (using own oocytes)

The most recent results available are from Assisted Reproductive Technology in Australia and New Zealand 2016, published September 2018.  This report provides success rates for IVF and FET (Frozen Embryo Transfer) cycles in all accredited fertility clinics in Australia and New Zealand during 2016.  The data shows the total number of cycles undertaken and the outcomes for all fertility clinics.  It therefore indicates average outcomes across all fertility clinics.  This excellent report is available at https://npesu.unsw.edu.au/surveillance-reports and patients are encouraged to access it directly.  In this section we will explain and discuss the information presented in this report.

Thaw cycles refer to embryo transfer using embryos which have been frozen and then thawed, or what we call a frozen embryo treatment cycle (FET).  See section Success Rates>IVF Success Rates for fresh cycle data.

The report uses the term ‘autologous’ which simply means that the embryos result from the use of the patient’s own eggs/oocytes.  Therefore it does not include donor oocyte cycles.  However, an autologous cycle can include either the male partner’s sperm or donor sperm.

The graph below is taken from a summary report from the website above.  It shows the progression of all 29,083 FET cycles which were started in 2016.

 

Of the 29,083 cycles initiated, 27,918 cycles progressed to embryo transfer.

Of these 27,918 embryo transfers, there were 9,921 clinical pregnancies and of these 7,930 progressed to a live birth.  (Please see Success Rates>Intro for explanation of clinical pregnancies).

Therefore the success rate of FET frozen embryo transfers was 9,921 clinical pregnancies from 27,918 embryo transfers, or 35.5%.

However, using live births, the success rate is 7,930 from 27,918 or 28.4%.

Live births from the FET cycles started is slightly lower at 27.3%.

Although the success rates for FET do not vary as widely as for IVF, it is still important not to assume that the success rate quoted is for live births from started IVF cycles.  The reason that the progression of FET cycles results in a much higher proportion of embryo transfers is that the areas of possible failure that occur in IVF cycles such as no fertilisation, or no oocytes collected, or freeze-all cycles have all been circumvented.  This is one of the reasons that  when patients undertake IVF cycles it is desired to achieve excess embryos which can be frozen for later FET cycles.