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Egg Freezing
Success Rates
Our success
Success rates are used to evaluate the performance of a clinic and can be used to help you decide which clinic to pursue treatment with.
Quality and quantity of eggs frozen
The success of egg freezing, and subsequent IVF treatment depends largely on the age of the egg used.
Egg quality in your 20s and early 30s is in general much better than when you are older. A better egg quality leads to a greater chance of pregnancy using these eggs. This is the principle on which egg freezing is based.
Egg freezing allows young women to freeze healthy eggs and preserve their quality. Depending on the age you are when you freeze your eggs, there will be an estimated success rate per embryo transfer. It is important to remember when viewing success rates that the age of the egg being used for treatment is more significant than the age you are when you use them.
Post thaw survival rates & expected number of embryos available for transfer
One of the measures of success of an egg freezing cycle is the proportion of frozen eggs that survive the thawing process. If you decide to use your frozen eggs in further fertility treatment, they must be thawed ahead of being fertilised. At London Women's Clinic, our egg thaw survival rate is 94%.
The greater the number of eggs that survive the thawing the process, the more eggs available for fertilisation and for the potential creation of embryos. However, not all thawed eggs will develop to produce an embryo, so it is important to discuss the number of eggs you are expecting to freeze and how many embryos this is likely to create in the future.
Live birth per embryo transferred
At London Women's Clinic, we measure live birth per embryo transferred, this represents the success of each individual embryo that is transferred and we're one of the first to share such record figures.
Although the proportion of egg freezing treatments is increasing, the number of people returning to use their frozen eggs for further fertility treatment, remains low. This low rate of use is understandable as women have up to 55 years to choose to return to use their frozen eggs, and have often frozen them as they are not yet ready to start a family.
At London Women's Clinic, our live birth rate per embryo transferred for women under 35 is well above the national average and we're one of the first to be able to share up to date, record figures of this nature. The latest HFEA certified data from 2018 for our clinic can be viewed on their website, where you can also compare and choose a fertility clinic. In general, success rates are of limited value when comparing centres and choosing where to seek treatment, but the figures below can be used as a guide for the potential success of future IVF treatment if you freeze your eggs when you are aged 35 years or less.
London Women's Clinic - live birth rates from own frozen-thawed eggs (2017-2022)
Overall - embryos transferred without further testing (total 239 cycles)
Genetically tested embryos* - embryos tested for normal chromosomes before transfer
*Live birth rates are doubled when embryos from frozen-thawed eggs are tested for normal chromosomes (PGTA-A) compared with those that are transferred without testing. Of the successful patients more than half still have genetically normal embryos in storage.
London Women’s Clinic works in partnership with London Egg Bank, the UKs largest donor egg bank. Results from the thawing of these donor eggs for use in IVF treatment cycles can be extrapolated to represent potential results for egg freezers. These two groups of patients are usually of similar ages and lifestyles, and their eggs will be frozen then thawed, fertilised and transferred, to create a pregnancy.
In a recent study of 559 consecutive recipients of frozen-thawed donor eggs, we reported a live birth rate per embryo transferred of 37.9%. Estimates of cumulative live birth rate following three embryo transfers is over 60% for these patients. We would expect data from women who have returned to use their own frozen eggs to produce similar success rates.
