Our success rates

Our specialist team is passionate about helping you achieve your dream of having a baby. In each treatment cycle the chances of this are very much dependent on the client’s own set of personal characteristics such as cause of subfertility, reproductive history, lifestyle factors and age.

Each and every cycle of treatment is therefore thoughtfully tailored to each client to achieve the best possible results. The live birth outcomes that are presented below, represent the most current average rates of success for IVF/ICSI fresh and frozen cycles based on all Australian and New Zealand clinics. 

However, because everyone’s chance of success is different, the presentation of average rates can be misleading and are therefore best explained during a personalised consultation with your fertility doctor. You can be assured that the clinics in New Zealand are all operating to the highest industry standards, so your choice of clinic will ultimately depend on the best fit and feel for you. The four most important things you need to know about success rates are:

  1. The fertility clinic you are planning to attend is operating to the highest clinical standards.
  2. How age affects the chance of getting pregnant and having a healthy baby.
  3. How success rates are presented in different ways.
  4. How lifestyle factors can affect success.

1. The fertility clinic is operating to the highest clinical standards

All clinics in New Zealand and Australia are required to report their live birth success rates to authorities (ANZARD) that analyse and publish the results so that clinics can benchmark themselves against acceptable clinical standards. The results for Repromed are assessed by our external auditors on behalf of the RTAC (Reproductive Technologies Accreditation Committee) and the New Zealand Health and Disability Standard Ngā Paerewa NZ8134.  

Additionally, clinics such as Repromed who provide publicly funded treatment, are also performance monitored six monthly by their Regional Health Authority. The endorsement of these authorities provide an assurance to patients that they are receiving the highest level of quality of care and outcomes.

2. How age affects the chance of success

As we age, the quality of our gametes (eggs and sperm) decline with time. 

Effect of age on eggs

Babies assigned as female at birth are born with a defined number of the eggs for the entire life of their reproductive life. This means that when someone is ovulating an egg, or having IVF in their 30s, the egg that is released or retrieved had been waiting dormant in their ovary.

This is why the older our eggs are, the more likely they will have been subjected to environmental and aging factors that reduce their quality and genetic normality. The graph below demonstrates how the abnormality rate of our eggs increases with age, and how this is directly related to a decline in the chance of having a live birth.

In vitro fertilisation statistics are internationally reported in age brackets of females undergoing treatment. From the table below you can see that the under 35 age group has the highest chance of a birth, while the most common age group who seek IVF treatment, the 35 to 39 year olds, has a 25% rate of having a baby. 

Importantly, live birth rates in females 40 years and older, decline to 9% per treatment cycle in fresh and 22% in frozen embryo transfer cycles.

Live birth rates table

Frozen embryo transfer cycles have the same if not higher chance of pregnancy than in fresh transfer cycles. This is mainly because the woman has not taken the ovary stimulating hormones which in some people may affect how receptive the uterus is to implanting embryos.

Effect of age on sperm

We now know that age also impacts sperm quality. Research has shown that DNA fragmentation within sperm is increased in men over 40 and has been significantly linked to an increase in miscarriage rates.

One study has demonstrated a 4% decrease in odds of having a live birth in people undergoing IVF for every additional year of the male’s age. Read more about the latest research in male fertility. 

3. How success rates are presented in different ways

It is important to understand there are many different ways results are being presented in the media and on clinic websites which calls for caution when interpreting them. To give you an idea of what this means, refer to the graph below which shows the progression of results that are reported based on the different stages of treatment.

Read more about understanding success rates in this helpful document from the Fertility Society of Australia’s website: How to choose an IVF clinic and understanding success rates.

Important points regarding success rates

  • Live birth is the most meaningful outcome, because not all clinical pregnancies (heartbeat seen at seven weeks) will result in the birth of a baby due to miscarriages. 
  • Pregnancy rate is interesting but not a recommended outcome as it can be easily misleading for people, who at the end of the day just want a live healthy baby. Number of embryos transferred can influence the results, as the more embryos are transferred, the greater the chance of pregnancy and twins. The standard practice in most clinics in Australia and New Zealand is to transfer only one embryo to minimise a multiple pregnancy. This is because multiple pregnancies affect the health and safety of the client and baby.
  • Success rates can be reported for different starting points. Per cycle started includes the 8% of cycles that are cancelled after starting the hormone drugs but before the egg retrieval (OPU) due to complications. Per egg retrieval includes all the clients who get to this stage and either have an embryo transfer (with or without freezing) or fail to have one due to either no eggs retrieved, failed fertilisation, failed embryo development etc. So results that only report per embryo transfer do not include all the clients who have failed to get to this point.
  • Freeze-only cycles are becoming increasingly common to protect both the client and the embryos if the conditions are not optimal for the embryos to create a pregnancy (e.g. OHSS and abnormal hormone profiles). This means that the number of cycles having fresh embryo transfer in Australasia is declining, because they have been converted to a frozen embryo transfer cycle.
  • Cumulative live birth rates refer to the combined chance of getting pregnant from each IVF cycle that results in a fresh transfer plus the subsequent frozen embryo transfer cycles (one or more). Some clinics will present results that state your chance of getting pregnant is, for example, 70% after two treatment cycles, which will include the frozen embryo transfer cycles that result from those two stimulated IVF treatment cycles.
Outcome of women of all ages

4. How lifestyle factors can affect success

The chances of success in each treatment cycle, is very much dependent on the client’s own set of personal characteristics such as cause of subfertility, reproductive history, lifestyle factors and age. However there is still a great deal that you can control regarding your lifestyle to better improve your chances. Read further about improving your fertility fitness.

Clinics in Aotearoa are all operating to the highest industry standards, so your choice of clinic will ultimately depend on the best fit and feel for you. Speak with your fertility doctor about your personal chances of success and taking home a healthy baby.


A helpful tool

The Australian Government has launched a website called Your IVF Success that provides independent and impartial information for those considering starting or continuing IVF. Although an Australian site, it may be helpful for Repromed clients to use the calculator in order to make informed decisions about IVF treatment, with the support of your Repromed fertility doctor.

Your IVF Success Estimator uses the main factors that are known to be associated with the success of IVF treatment. The estimate generated is based on the information you enter, and the chance of a live birth based on people who have had IVF treatment in Australasia with the same characteristics as you. The prediction is derived from the annual data collected by the National Perinatal Epidemiology and Statistics Unit (NPESU) of the University of New South Wales Sydney (UNSW) from all licenced New Zealand and Australian IVF clinics.

While the Estimator is a welcome innovation for those who wish to get a ballpark idea of the chance of success, there is a strong recommendation that it should be used in conjunction with your Fertility Specialist’s advice and guidance. This is because the estimate provided may not fully reflect the impact of your own individual clinical situation that would take into account such factors as your AMH (egg reserve) level.

Click here to use the Estimator. 

Please note that the advice and information is not associated with Repromed, please discuss any queries with your Repromed doctor. 

Megan Black

Nurse Manager


Megan leads the nursing team through the continually changing face of IVF. She works in a multidisciplinary team, providing the essential organization between the doctors and laboratory and ensuring communication between all departments.

Megan started her IVF nursing career in the United Kingdom, working in two large London clinic’s before returning to New Zealand. She is also the Secretary of Fertility Nurses of Australasia.

I love working with people and see nursing as a vocation, not a job. I usually spend my downtime absorbed in a good book and planning my next travel adventure.