IVF Success Rates Explained

Judging fertility clinics abroad on the basis of their success rates is one of the most widely used methods patients use to help them choose their ideal IVF (in vitro fertilization) clinic but unfortunately, it is not always the wisest one. You might ask why this is so but in fact success rates are not solely achieved by the actions of the clinic but rather they are the result of a number of interrelated factors. The clinic plays a large part as a result of the professionalism and experience of its fertility team and the technologies employed in fertility treatments but so too do patients.

In the majority of cases it is a patient’s individual situation, their fertility problems, and medical history which influence the final result of the treatment rather than the clinic itself. A woman’s age, genetic factors or various reasons for infertility play a crucial role in determining IVF success.

It is highly advisable to do your own research prior to choosing the best fertility clinic abroad. Always analyse all the medical and psychological aspects that the IVF treatment process entails and only choose to proceed if you ready to commit financially to what can be a substantial investment.

How IVF success rates are calculated and presented by fertility clinics

There is not a standard and accepted way for treatment providers to share information regarding success rates of IVF. Comparing IVF treatment success rates between clinics in the same country can be challenging sometimes but when you attempt to compare rates between different countries the task becomes even harder. Defining, calculating and reporting IVF procedure success rates varies between clinics and as a patient you should be aware that the criteria used to define these rates will impact greatly on the final figures quoted.

To help you distinguish between the various criteria clinics employ to report success rates we have illustrated some of the benchmarks used to present and calculate rates.

IVF success rates presentation

IVF success rates presentation involves various benchmarks and methods used by clinics to report and calculate their success rates. These methods can include success rates per start of the cycle, per embryo transfer, and cumulative success rates over multiple cycles. Understanding these different criteria can help patients better interpret the figures and assess their chances of achieving pregnancy.

IVF success rates per start of the cycle

This method of reporting success rates is based on the chances of success with repeated cycles rather than on one cycle. This criterion is useful for patients who are assessing their overall chance of achieving pregnancy and is a very accurate tool if it is combined with age or a patient’s medical condition.

IVF success rates per embryo transfer

This reporting method is usually calculated on the basis of the number of patients reaching the stage of having embryos that are ready to be transferred. This rate does not refer to clinical pregnancy rates or live birth rates that can vary from this baseline figure.

Cumulative IVF success rates

This method is used to reflect the overall effectiveness of a particular treatment over a specific number of cycles.

IVF success rates calculation

IVF success rates calculation can vary significantly based on different outcomes such as biochemical pregnancies, pregnancies at week 12, and live births. These variations make it challenging for patients to analyze and compare success rates effectively, especially when clinics use different criteria.

A biochemical pregnancy

A biochemical pregnancy refers to a miscarriage within the first four or five weeks of the embryo implanting.

Pregnancy at week 12

This is usually when the first ultrasound takes place and is the moment when the foetus is fully formed.

Live birth

This calculation is triggered when a baby is born and displays signs of life whatever gestational age it has reached.

It is easy to see therefore why so many patients find trying to analyse and compare success rates so difficult when they are presented in different ways and calculated on the basis of different outcomes. The IVF success rates you will see on clinic websites will invariably be generic, that is to say, they will be measured against patients with different treatment requirements which could be as diverse as male factor infertility or ovulatory disfunction. It may also be difficult to compare a generic clinic with one that helps patients with a specific condition like low ovarian reserve – the latter may be more successful at treating such patients than generic clinics but due to the nature of the condition it follows that their overall success rate may appear low in comparison with other providers.

IVF success rates by country—a comparison

There are differences in IVF outcomes between popular countries. It is not recommended, however, to assess the treatment quality between countries solely based on IVF success rates. Differences in IVF success rates between countries may not reflect differences in the quality of IVF treatment between countries – and the same rule applies when comparing the IVF clinics.

Success rates of IVF by age—European IVF clinics

The effectiveness of IVF treatment with own eggs will vary significantly depending on the age of a female patient. Additionally, there are many other parameters that influence the effectiveness of treatment. These include, amongst others:

• age of a woman 
• BMI
• quality and the number of oocytes collected 
• quality of the male partner’s sperm

That is why it is so important to always ask about your own individual chances and not about average IVF success rate of a clinic. When publishing data on treatment effectiveness, the best clinics will take different patients’ age groups into account. However, this still might not be sufficient to be able to effectively compare success rates between IVF clinics.

The risk is known to increase with maternal age. Pre-implantation screening can improve implantation and pregnancy rates and maximises the opportunity of transferring only euploid (chromosomally equal) embryos. The aneuploidy testing follows an embryo biopsy, where a small number of cells are removed and then analysed.

Dr. Yadira Pallás Gálvez, an embryologist from the Reproduction Unit of Hospital Clínica Vistahermosa explains

The following table draws upon data collected from European registries by ESHRE (European Society of Human Reproduction and Embryology) and provides a really useful comparison of live birth rates by patient age and shown as percentages. The first thing you will notice about the data is that there is a substantial decrease in IVF success rates for women over 40 with the exception of one country. The optimum age for IVF with own eggs is under 34 and success rates can fluctuate anywhere between 25% and 30% and there is also a smaller decrease in success rates for those women aged between 35 and 39 compared to their younger peers. The exception to most of these figures is Latvia but with only five clinics and a smaller number of cycles being carried out in the country compared to somewhere like Spain you would expect to see rather different results.

This comparison table is a useful starting point but as we shall see throughout this article, success rates are subject to complex variables and are collated and presented in different ways.

Source: ART in Europe, 2017: results generated from European registries by ESHRE*
Supplementary Table SX Aspirations, pregnancy and delivery rates by age distribution (years) of women treated with ICSI in 2017.
Pregnancies per embryo transfer.
**North Cyprus is the self–proclaimed state recognised only by Turkey and is not providing and data to ESHRE EIM Consortium.

Success rate of IVF with donor eggs—Europe

In the case of donor egg success rate, the effectiveness is independent of the patient’s age. However, remember that your own treatment history and its medical parameters may be important for the expected result. That is why you should always ask the IVF experts about your personal chances of success and not about the average effectiveness of treatment.

The following table produced by ESHRE (European Society of Human Reproduction and Embryology) uses data collected by different European registries to show success rates in countries that offer fresh and frozen egg donation treatments. No information is recorded about the age of patients as this does not have any direct impact on outcomes.

Interestingly the countries that perform the largest number of cycles in Europe including Spain suggest that fresh cycles appear to attract a higher success rate. IVF success rates for frozen cycles vary between 34.4% in Poland to a high of 61.6% in Ukraine. According to the data which was recorded in 2017 Ukraine achieved the highest frozen cycle success rates at 62.2% and this compared to the lowest success rate of 23.1% which was recorded in the Czech Republic.

Once again, although this table is useful do remember that success rates may be collated and presented differently by clinics and countries.

Source: ART in Europe, 2017: results generated from European registries by ESHRE*
Supplementary Table SVIII Pregnancies and deliveries after ED (fresh and frozen cycles) in 2017. In Egg Donation cycles, the age of the recipient women had no influence on outcomes. Pregnancies per embryo transfer (fresh and frozen)
**North Cyprus is the self–proclaimed state recognised only by Turkey and is not providing and data to ESHRE EIM Consortium.

IVF success rates in the USA

The IVF success rates in the USA are monitored by SART (Society for Assisted Reproductive Technology) and published by CDC (Centers for Disease Control and Prevention). Due to the large number of cycles and accurate data collected from IVF clinics, SART may be a very good reference point for any patient undergoing IVF treatment.

IVF with own eggs—success rates by age in the USA

The average IVF procedure success rates – live births – for IVF with own eggs (including patients with all types of infertility diagnosis) in the USA are:

• 49.7% for women younger than 35
• 44.8% for women aged between 35 and 37
• 39.6% for women aged between 38 and 40
• and 22.6% for women older than 40

The IVF statistics above are presented as the percentage of embryo transfers resulting in live-birth deliveries and the results are based on 107,795 IVF cycles (2019)*.

IVF with donor own eggs (egg donation)—success rates in the USA

The average success rates of IVF transfers with donor eggs – live births – (including patients with all types of infertility diagnosis) in the USA are:

• fresh oocytes from the donor (fresh embryo transfer): 53.9%
• frozen oocytes from the donor (fresh embryo transfer): 45.8%

The IVF statistics above are presented as the percentage of embryo transfers resulting in live-birth deliveries and the results are based on 24,042 egg donation cycles (2019)*.

*Source: Assisted Reproductive Technology (ART) by National Center for Chronic Disease Prevention and Health Promotion, Division of Reproductive Health

IVF success rate—UK

We have provided data in the following tables which illustrate some interesting differences between published success rates in the UK and Europe. Although there is no definitive data which points to the number of patients who travel abroad for fertility treatment from the UK we are aware that this number is significant. Feedback from patients themselves and clinics throughout Europe suggest that UK patients continue to travel for various reasons and this number does not appear to be reducing at all.

Patients from the UK obviously travel for different reasons. It may be down to success rates advertised by non-UK clinics or a combination of other variables including costs, access to treatments for older women, reduced waiting lists, access to treatments not readily available or legal in the UK, or because of the better availability of egg donors.

You will notice that overall success rates of IVF quoted in the UK tend to be bit lower than their European equivalents. However, it does better on average than European countries in terms of treating younger patients seeking IVF treatments using their own eggs. For instance, the UK boasts an average success rate of 32% for women under 35 using their own eggs – this figure is higher than in the European countries (showed as a pregnancy per embryo transfer) we feature in this article although it remains significantly lower than the figure quoted in the U.S. However, the IVF success rates for 40+ women appear to be lower than in European countries – this may be one of the reasons why a large number of women over 40 travel from the UK for IVF treatment and consequently the overall number of women who collectively receive IVF cycles in Europe is higher than the absolute number in the UK.

The differences in success rates between the UK are Europe are more significant when we consider success rates for treatments involving egg donors. In general, terms if we take overall success rates European treatment providers offer success rates which are 10% above the UK average – even if we consider differences in data presentation – in the table above the egg donation success rates are presented as pregnancy per embryo transfer while in the UK they are presented as live births. We know from different countries that the reasons for patients travelling from the UK include the desire for anonymous donors and cost as well as success rates. The majority of those travelling from the UK are seeking IVF treatments with donor eggs and the number of such procedures in Europe dwarfs the number undertaken in the UK. The availability of donors and no waiting lists are also drivers for more patients travelling from the UK.

IVF success rates in the UK are published by the HFEA (Human Fertilisation and Embryology Authority) – the UK fertility regulator.

The IVF success rates for IVF with own eggs by age in the UK

The IVF success rates for IVF with own eggs by age in the UK vary significantly:

• 32% for women under 35
• 25% for women aged between 35 and 37
• 19% for women aged between 38 and 39
• 11% for women aged between 40 and 42
• 5% for women aged between 43 and 44
• 4% for women aged between 45 and 50

IVF statistics above are presented by HFEA as birth rates per embryo transferred and the results are based on 40,358 IVF cycles (2019)*.

The IVF success rates for transfers with donor eggs by age in the UK

Understanding these success rates within the context of age is crucial for individuals contemplating fertility treatments involving donor eggs:

• 34% for women under 35
• 37% for women aged between 35 and 37
• 31% for women aged between 38 and 39
• 33% for women aged between 40 and 42
• 35% for women aged between 43 and 44
• 31% for women aged between 45 and 50

IVF statistics above are presented by HFEA as birth rates per embryo transferred and the results are based on 5,368 egg donation cycles (2019)*.

Source: Fertility treatment 2019: trends and figures by HFEA

IVF success rates and choosing an IVF clinic

While success rates are an important factor when choosing an IVF clinic, it’s essential to look deeper into how these rates are calculated. Consider whether the statistics are relevant to your personal fertility journey—taking into account your age, medical history, and diagnosis.

A clinic’s ability to provide a personalized treatment plan is just as crucial as its overall success rate. Clinics in countries like Spain, Greece, and the Czech Republic are known not only for their high success rates but also for their individualized care and patient support. By considering both success rates and the clinic’s approach to treatment, you can make a well-informed decision that aligns with your needs.

Misleading IVF success rates​

Even if data regarding clinic success rates comes from a public report you still need to apply a degree of caution. Firstly, remember that clinics can be ‘creative’ when measuring and reporting their success rates. They quite understandably want to show the highest numbers possible to encourage more patients and these figures will often appear to be significantly higher than the reported national average.

There is nothing wrong per se with the fact that an IVF clinic will want to calculate success rates based on their particular algorithm but be aware that those clinics with higher success rates will ordinarily want to charge higher prices. It is therefore important for you to ensure these success rates are appropriate in your specific case.

It is worth also applying caution to IVF refund programmes which are now gaining popularity, which may “promise” a 100% success rate or a live birth. Such IVF packages are financial programmes that involve risk-sharing between the clinic and patients. From a purely medical perspective, they can’t guarantee anything (for instance, success rates, pregnancy success, live birth) but merely offer a money-back guarantee – “a refund” based on the expected outcome. That’s why they are often called IVF refund – guarantee programs.

IVF success rate calculator

How to check the prospects of a successful outcome based on your individual history?

Increasingly we are seeing technology employed to predict the likely outcomes of IVF treatment and the more sophisticated AI becomes the more likely we are to see more accurate predictor models.

One of the most accurate models that has been developed to predict the potential success of particular treatments was developed by the Society for Assisted Reproductive Technology (SART) in the United States. The SART Patient Predictor is a very sophisticated tool that has been evolving since 2006. Based on continual analysis of over half a million cycles and over three hundred thousand women the calculator is designed to predict the chances of successful outcomes based on an assessment of each patient’s personal situation.

Patients are requested to answer questions relating to their physical self such as height and weight as well as medical questions about any diagnosis they may have received. Each calculation is highly personalised and is based on the assumption that the individual has not received any IVF treatment prior to recording their details.

The patient predictor will then attempt to accurately predict your chances of a live birth as well as proving advice and information on the risks that might be associated with any IVF treatment. For instance, SART might predict the chances of multiple births as a result of multiple embryo transfers and quantify the danger from such procedures.

It is worth noting that the SART predictor is only one of the tools available to assess potential IVF outcomes and only features data captured from U.S. patients. As technology develops we are likely to see more tools which attempt to forecast outcomes and inevitably these will become more accurate in time.

One last caveat from us if you are thinking of, or currently using a predictor tool, it is always worth comparing the predicted success rates with the clinic of your choice. If there is a significant difference between a predicted figure and the success rate quoted by the clinic you will need additional time to evaluate the figures.

You may be interested in reading more about: IVF success rates calculators

IVF success rate—other resources​

If you are looking for more information regarding chances of success when going through an IVF cycle we highly recommend checking out the resources below:

• The importance of 3 full cycles of IVF
• IVF success rate questions – questions answered by multiple fertility experts
• IVF success rate – USA national data by SART
• SART – IVF outcome predictor
• Choose a Fertility Clinic

Let TOP IVF specialists review your chances of IVF success

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IVF success rates – FAQs