Egg Freezing Success Rates
If you’re thinking about investing the time, money and emotional energy in freezing your eggs, you will want to know what the outcomes of that will be.
The truthful version is this: egg freezing preserves a possibility, not a certainty. It can give you a chance of having a biological child later — but it isn’t an silver bullet or a guaranteed insurance policy, and no clinic, calculator or advisor can promise you a baby at the end of it. The HFEA, the UK’s independent fertility regulator, puts it plainly: egg freezing is becoming more successful but is by no means a guarantee of having a baby.
This article walks you through what the journey from a frozen egg to a live birth actually looks like, why the numbers can feel opaque, and how to read success rates without being misled or overwhelmed.
The chain from egg to baby
When clinics talk about “success rates”, they often mean different things. To make sense of any figure you’re shown, it helps to understand the process from egg to live birth — and at every step, there are challenges and risks
Here is the chain, in order:
1. Eggs retrieved. After hormone stimulation, your clinic collects eggs from your ovaries. According to the HFEA, most patients under 38 will have around 7–14 eggs collected, although this isn’t always possible for those with low ovarian reserve.
2. Mature eggs frozen. Not every egg collected is mature enough to freeze. Only mature eggs go into the freezer using vitrification, which is fast freezing in liquid nitrogen.
3. Thaw survival. When you come back to use them, the eggs are warmed. Some don’t survive. In a 2023 UK cohort study at Guy’s Hospital in London, the average egg survival rate after thaw was around 74%.
4. Fertilisation. Surviving eggs are fertilised with sperm using ICSI (a single sperm injected into each egg). In the same Guy’s Hospital study, the average fertilisation rate was around 67%.
5. Embryo development. Fertilised eggs need to grow into healthy embryos. Some stop developing along the way. This is normal and largely reflects egg quality at the time of freezing.
6. Embryo transfer. A healthy embryo is transferred to the uterus.
7. Pregnancy and live birth. Not every embryo transfer leads to a pregnancy, and not every pregnancy leads to a live birth.
In the Guy’s Hospital cohort, the pregnancy rate per embryo transfer was around 48% and the live birth rate per embryo transfer was around 35%. That’s per embryo transfer — not per egg frozen — which is an important distinction we’ll come back to.
Why the number of eggs matters
Because eggs are lost at every step in the chain, the number you start with i.e. the number you choose to freeze really matters. A single frozen egg has a small chance of becoming a baby but larger group gives the process more opportunities to work. And because age is linked to egg quality, the number of eggs recommended vary by age group.
One widely cited model from researchers in the Journal of Human Reproduction estimates:
If you freeze 20 eggs at age 34, you may have around a 90% chance of having at least one baby
If you freeze 20 eggs at age 37, that drops to around 75%
If you freeze 20 eggs at age 42, it drops significantly to around 37%
More recent UK research has reached a similar conclusion: pregnancy and live birth rates are encouraging if eggs are frozen at a younger age, and if 15 or more eggs are frozen per patient, irrespective of age at freezing.
A few practical things to take from this:
One cycle doesn’t always produce enough eggs, especially if you’re over 35 or have a lower ovarian reserve. Some women need more than one cycle to bank a meaningful number.
“How many eggs is enough” depends on how old you are when you freeze, and on how many children you eventually hope to have.
Quality matters as much as quantity. Twenty eggs at 32 are not the same as twenty eggs at 40.
Why your age at freezing matters more than your age at thawing
This is one of the most important things to understand about egg freezing.
When you freeze your eggs, you’re essentially preserving them at the quality and chromosomal health they have on that day. The HFEA has been clear that while a woman’s age at thaw has relatively little impact on her chances of success, her age at freeze does.
This is why so many fertility specialists talk about the “ideal window” for egg freezing being between roughly 30 and 36 — old enough that you may genuinely use the eggs, but young enough that the eggs are likely to be of good quality and reasonable number.
In the UK, however, the reality is different. According to the HFEA, the average age of patients freezing their eggs in 2023 was 35, and the average age of thawing was 40. Many women come to the decision later than would be biologically optimal — often because life circumstances, awareness, or finances make earlier freezing difficult.
There’s no judgement in this. It’s just useful to know, the younger you freeze your eggs the better the statistical chances tend to be.
Why a clinic’s average success rate may not apply to you
Clinic websites often advertise impressive-looking success rates. These figures are not necessarily wrong, but they can be misleading if you don’t know what’s behind them.
Here are some honest questions to ask:
Is this rate per egg, per cycle, per thaw, per embryo transfer, or per patient? Each gives a different number, and clinics can choose which to highlight.
Does the figure include donor eggs? Donor eggs come from younger women, so they push success rates up. The HFEA has reported that the birth rate per cycle from frozen donor eggs was around 30%, compared to 18% for women using their own thawed eggs. If donor and own-egg cycles are mixed in a single number, that average may not reflect what you should expect.
What is the age band? A “44% live birth rate” is meaningless without knowing the age of the women included.
How many cycles is the figure based on? Small numbers (a handful of patients) can produce wildly different percentages from year to year.
The HFEA itself acknowledges that frozen-egg numbers in the UK are still relatively small, which makes statistics noisy. As the regulator notes, the technology has improved over the years, which means older data isn’t comparable to current success rates. They recommend looking at fresh IVF success rates in your own age band as a more reliable benchmark, since far more fresh cycles take place each year.
What the UK numbers actually show
A few things are worth knowing about the current UK picture, drawn from the HFEA’s most recent Fertility Treatment 2023: trends and figures report:
Egg freezing cycles in the UK increased from 2,567 in 2019 to 6,932 in 2023 — a 170% rise — and now account for around 7% of all treatment and storage cycles.
The largest increases have been among women in their 30s, with cycles among 30–34 year olds rising from about 1,200 in 2022 to 2,000 in 2023, and among 35–37 year olds from 1,500 to 2,300.
Despite the growth, the number of patients returning to use their stored frozen eggs remains low.
That last point matters. Most women who freeze their eggs in the UK have not yet come back to use them. This means we still don’t have large, fully mature UK datasets on real-world live birth outcomes from elective egg freezing. The picture is improving year on year, but the honest summary remains: we know more than we did, and less than we’d like.
What the research community currently agrees on
The American Society for Reproductive Medicine, the HFEA, and the Nuffield Council on Bioethics all converge on the same broad messages:
Vitrification (fast freezing) has substantially improved outcomes compared to older slow-freezing methods.
Younger age at freezing is the single biggest predictor of success.
More eggs frozen generally means a higher chance of at least one live birth — particularly for women freezing at 35 or older.
Outcomes data are still maturing because uptake of stored eggs is low and the technology is relatively young.
Bringing it back to you
Numbers are useful, but they describe groups of women — not you. Your own chances depend on a mix of personal factors: your age, your ovarian reserve (often estimated using AMH and antral follicle counts), your overall health, your partner’s sperm quality if and when you come to use the eggs, and how many eggs you’re able to bank.
This is why we always say at Egg Advisor: averages are a starting point, not an ending point. The most useful conversation is the one you have with a fertility specialist who can look at your test results, your history, and your hopes — and give you a personal estimate.
Whatever you decide, you deserve information that is honest about what’s known and unknown. We hope this article helps you ask sharper questions and feel a little less alone in the uncertainty.
Want to explore your own numbers?
There are several egg freezing calculators online. Egg Advisor doesn’t recommend one over another, and we’d suggest trying a few to get a balanced picture, since each is built on slightly different datasets and assumptions.
One of the newest, and one of the few that isn’t run by a private clinic, is the YourEggFreeze Estimator, launched in March 2026 by the University of New South Wales’ National Perinatal Epidemiology and Statistics Unit and funded by the Australian federal government. It uses real-world data from Australia’s national IVF registry, which includes information from every IVF clinic in Australia, and lets you enter your age and the number of cycles you plan to do to receive a personalised estimate of how many eggs you can expect to freeze and your estimated chance of having a baby from those eggs.
If you’d like to talk through what success rates might look like for your specific situation, you can always book a one-to-one appointment with an Egg Advisor.