Understanding success rates
The HFEA has now excluded all PGT-A-tested embryos from clinical success rates data. This means that when viewing the HFEA data, you may not be seeing the results of all embryos transferred at a clinic.
This is why we will show you our data, as published by the HFEA, and also our data for ALL embryos we’ve transferred at The Evewell.
The HFEA have two measures of success: births per embryo transferred and multiple birth rate. These are all important factors to understand when choosing a fertility clinic, but what do they mean?
The term “births per embryo transferred” means the number of babies born for every embryo placed back inside the womb.
This is different to “births per embryo transfer“, which could mean multiple embryos are placed back inside the mother.
This also means that any single embryos transferred that result in a twin (identical) birth are counted as one.
Multiple pregnancies are a risk when having fertility treatment, not only for the person carrying the babies and babies, but also for any problems that can sometimes be lifelong.
It’s now best practice to transfer only one embryo during an embryo transfer event to reduce the chance of multiple pregnancies, which can pose serious risks to both the mother and babies.
The HFEA closely monitors all fertility clinics’ multiple birth rates to ensure they are as low as possible. It’s important when choosing a clinic that you’re aware of their multiple birth rate.
Understanding IVF Success Rates
What Does 'Births per Egg Collection' Mean?
Why we only use HFEA-verified data
Some clinics present “success rates” using their own definitions or metrics, such as “pregnancy rate” or “live birth rate per patient”, which can make them look better on paper. However, this makes it hard for fertility patients to compare clinics and creates ambiguity.
The HFEA and CMA have clear guidance on how data should be collected and reported, including “live birth rates per embryo transferred”. By following these rules, patients get a true picture of how clinics perform.
We commit to:
- Publishing figures verified by the HFEA
- Presenting our data exactly as the HFEA and CMA require
- Avoiding cherry-picked data or selective patient groups
- Welcoming patients of all ages and reproductive health backgrounds
A 47% chance of a having a baby at The Evewell
Based on the most recent HFEA data, our success rates put us in the top three fertility clinics in the UK.
The following data is from treatment cycles at The Evewell Harley Street and The Evewell West London from January to December 2023, compared with the national average for treatments performed in 2023, as reported by the HFEA.
* vs. the HFEA national average of 28%, for live births per embryo transferred, excluding PGT-A tested embryos.
Babies born per embryo transferred at The Evewell West London in 2023
Against 2023 HFEA national average
HFEA Grouped Data - West London
The HFEA presents all fertility clinic data into ‘Under 38′,’ 38 and over’, and ‘All patients’ data sets. Please see the chart below for a further age breakdown, so you can see your own individual chances of success rates based on your age group.
Babies born per embryo transferred at The Evewell West London in 2023
All embryos, including PGT-A tested embryos
Building families
We work hard to give our patients options and choices, minimising pregnancy loss and creating families, both now and in the future.
Our results for babies per embryo transferred are significantly higher than the national average, thanks to the collaborative efforts of our clinical team and embryologists, who are focused on optimising every cycle and giving future family-building options to our patients.
Babies born per embryo transferred at The Evewell Harley Street in 2023
Against 2023 HFEA national average
HFEA Grouped Data - Harley Street
The HFEA presents all fertility clinic data into ‘Under 38′,’ 38 and over’, and ‘All patients’ data sets. Please see the chart below for a further age breakdown, so you can see your own individual chances of success rates based on your age group.
Babies born per embryo transferred at The Evewell Harley Street in 2023
All embryos, including PGT-A tested embryos
Maximising Chances
We don’t select patients based on age or fertility history, and where appropriate, do as much as we can in the pre-transfer stage to optimise the chances of success, for example: incorporating gynaecological investigations and further tests into your treatment plan.
In addition to being highly ethical and treating every embryo with the care and respect they deserve, fertility treatment at The Evewell is both personalised and collaborative, with the entire clinical team reviewing every patient in our daily “All Hands” meetings.
Why fair comparison matters
We believe every patient deserves the truth. That means not using our own, unverified metrics to appear better than others. We encourage all UK fertility clinics to do the same, so that when you compare, you’re looking at real, like-for-like data.
Please note that there is a limit to what success rate data can show, and we recommend that patients use them as a guide only. Multiple factors, such as personal medical history, will affect treatment outcomes. Therefore, it is important to discuss your individual chances of success with your consultant.
Information on success rates is only one factor when choosing where to seek treatment and comparing fertility clinics. The HFEA’s ‘Choose a Fertility Clinic’ function is a useful source of information. For further information, clinic success rate comparisons and advice on choosing a clinic, please see the HFEA guidance.
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