Understanding success rates

Different clinics report success in different ways. We use the chance of a baby from a single treatment cycle.  For IVF, this includes using both fresh and frozen embryos (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.

Modern fertility treatments give you the same or better chance of a baby per month than nature does for fertile couples.

The chart below shows the chance of a live birth by age - highlighting the differences between IVF, IUI and natural fertility.  The IVF data is based on birth rate from fresh embryo transfer and the use of any frozen embryos within 6 months from the same egg collection.

Fertility Associates’ actual data from IVF cycles started between 2011 and 2013.

How do we compare?

Fertility Associates has excellent success rates that are well above the American average, embryo for embryo.


We compare our success rates with clinics in the USA, as they have some of the highest pregnancy rates internationally and their clinic results are published with enough detail to allow accurate comparison. 

The graph below shows the chance of a single embryo giving rise to a baby at Fertility Associates compared to the USA average*, following fresh embryo transfer.

We used to compare our success rates with clinics in Australia, however this information is no longer available.

*We can’t compare pregnancy rates with the USA directly, because American clinics usually transfer two embryos at a time, unlike in New Zealand where we transfer one embryo at a time for the mother and child’s safety. 

Because we perform around 65% of all fertility treatment in NZ, our results are representative of the New Zealand population.


Fertility Cover

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

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 pregnancy rate.

Our Fertility Cover programme gives you 3 chances to have a baby, with a 70% refund if you are unsuccessful. The programme has been going for 3 years, with 80% of people starting Fertility Cover having a baby.

About 85% of patients aged 39 or younger are eligible for our Fertility Cover programme.



Your personalised chance of success

When comparing success rates, check that what you’re looking at is relevant to you. The major factors contributing to individual success are:

  1. The woman’s age at egg collection
  2. The number of eggs collected

All our graphs show birth rate by the woman’s age. 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.

The usual test for measuring how many eggs you are likely to have ‘ovarian reserve’ is an AMH (Anti Mullerian Hormone) test. Our doctors customise the dose of medications and the type of ovarian stimulation to use 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.

Meet the team