Understanding IVF success rates

Different clinics report fertility treatment success in different ways. We use the chance of a baby from a single treatment cycle.  This is also the preferred way to report results for the New Zealand consumer group, fertilityNZ, the Fertility Society of Australia and New Zealand,  and SART (the Society for Assisted Reproductive Technology) in the United States

For IVF, this includes using both fresh and frozen embryos from a single egg collection.  Over half our births from IVF in younger women come from using frozen embryos. 

When selecting a clinic, it’s important to check what measure they use when reporting their success rates. Many use ‘clinical pregnancy per embryo transfer’, which excludes:

  •       People who do not have any eggs
  •       People whose eggs don’t fertilise
  •       Pregnancy loss or miscarriage

Clinical pregnancy rate per transfer can also be increased by transferring more than one embryo at a time, which carries the risks and complications of twins and even triplets to the mother and children.

Our booklet Pathway to a Child has comprehensive information on the chance of success with IVF and other treatments. 

Here are our most recent results for a single IVF egg collection cycle.  It covers all women using their own eggs who have an egg collection, including those who did not get any eggs, those whose eggs didn’t fertilise, those who do not have an embryo suitable for transfer, and those whose pregnancy sadly miscarried.


The figure above is based on all egg collections at Fertility Associates clinics for 2019-2020 with follow up for a year.  These results cover IVF cycles with normal fertilisation and sperm microinjection. We transfer fresh embryos at the cleavage or blastocyst stage, while thawed embryos are nearly always transferred at the blastocyst stage. About 10% of cycles started do not get to egg collection. For most of these people, it is better to stop, and start again with a higher dose of the medications used for ovarian stimulation.

Your personalised chance of success

It is your personal chance of success per treatment that is important. The major factors contributing to individual success are:

  •       The woman’s age at egg collection
  •       The number of eggs collected

If you are using an egg donor, it is the donor’s age that matters. When using frozen embryos, it is your age when the embryos were created.

Your doctor will advise whether other personal factors, such as cause of infertility, weight, or sperm quality, that might affect your chance of success.

The numbers you are likely to have in an IVF cycle can be estimated from the level of a hormone called AMH (Anti Mullerian Hormone). Our doctors customise the dose of medications and the type of ovarian stimulation based on your age, AMH level, and other information from your medical history. Having 5-10 eggs gives about twice the chance compared to having 1-2 eggs. However, having more than 10 eggs only adds a small extra benefit.

The chance is very similar whether it is your 1st, 2nd or 3rd cycle, unless some major problem or issue shows up in the first cycle.

The number of eggs can vary from one IVF cycle to another; the number is usually within plus or minus 3. So if you get 8 eggs the first time, you can expect 5 to 11 eggs the next time.


The Australian Reproductive Technology Accreditation Committee (RTAC) also requires clinics to present results as birth rates per fresh embryo transfer and per frozen embryo transfer.


Here are our results from 2020 -2021.  Keep in mind that not everyone will have an embryo suitable for transfer.  On the other hand, many people will be able to have two or more embryo transfers from a single IVF egg collection cycle. 

In nearly all our embryo transfers, only one embryo is transferred at a time to optimise the mother’s and child’s safety.  ‘One at a time’ maximises your overall chance of a baby and your safety.

The green (fresh) and blue (thaw) lines are ‘every day results’.  The purple line shows birth rates for embryos which have had Preimplantation Genetic Testing to ensure the correct number of chromosomes (abbreviated PGT-A).  As women become older, more embryos have the wrong number of chromosomes, which means PGT-A can be useful for choosing which embryo to transfer in women aged 38 and older.


How do we compare?

The Australian government has created a website called www.yourIVFsuccess.com showing patient characteristics and success rates for all the clinics in Australia.  NZ clinics are excluded from this website, but our graphs above of the cumulative birth rate after a single egg collection cycle and birth rates for embryo transfer of fresh and thawed embryos follow the format of key data in this website.


Some clinics use wider age bands than we have used above, so this table may be useful:

*For treatments performed in 2020 & 2021.

Fertility Cover

Many clinics make promises, but we put ourselves on the line with our Fertility Cover programme.

We are the only clinic in Australia and New Zealand that does this.

Just like nature, fertility treatment may take some time to achieve success. The chance of having a child after 1, 2, 3 or more cycles is called a cumulative birth rate.

Our Fertility Cover programme gives you up to 3 chances to have a baby, with a 70% refund if you are unsuccessful. The programme has been going for 10 years.  About 85% of patients aged 39 or younger are eligible for our Fertility Cover programme.

The following table shows the birth rate after 1, 2 and 3 cycles of people on our Fertility Cover programme.


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