When Should You Freeze Your Eggs?
Of all the questions women ask us at Egg Advisor, this is the one that comes up most often. And it's the hardest one to answer in a single sentence — because the honest answer is: it depends on you.
There's no universally “right” age. There's no perfect month, year, or life moment that science can pinpoint for everyone. What we can do is help you understand the two things that matter most when timing this decision: how your eggs change over time, and what your own fertility picture looks like right now.
Why age is the headline number
You may have heard this before, but it's worth saying gently and clearly: women are born with all the eggs they will ever have. Unlike sperm, eggs aren't replenished. From the moment you're born, the number is steadily falling, and from your mid-thirties onwards, the speed of decline picks up — and picks up again in your forties. The rate of decline is different for everyone and overall it is very hard to pinpoint.
Two things change with age — not just one:
Quantity — the total number of eggs in your ovaries.
Quality — whether each egg has the right number of chromosomes to make a healthy pregnancy.
Quality is the quieter of the two, and often the most surprising. Drawing on data from embryos tested during IVF, around 60% of embryos have the correct number of chromosomes at age 35, falling to roughly 30% by age 40. Eggs with missing or extra chromosomes usually don't lead to a pregnancy, or they end in early miscarriage. This is why your age at the time of freezing — not the age you use the eggs — is the single biggest factor in success later on if you decided to use your eggs.
So when fertility specialists say “younger eggs do better,” they're not being dismissive of women in their late thirties or forties. They're describing a broad biological principle.
So what’s the “best” age to freeze?
Honestly, there isn't one — but there are sensible windows, and they look slightly different depending on what you're optimising for.
Best for biology: Between 20 and 30, when egg quality and quantity are at their highest. The catch? Most women in this age group also have the best chance of conceiving naturally and may never need their frozen eggs.
Best for cost-benefit: Studies looking at the value of freezing tend to land around age 36 — eggs are still reasonably good quality, and you're statistically more likely to actually use them.
The practical sweet spot: Most clinicians, when asked, suggest somewhere between 30 and 36 — a balance of good egg quality, a higher number of eggs collected per cycle, and a sensible runway before quality declines.
What's actually happening on the ground? In the UK in 2023, the average age at egg freezing was 35, and the average age at thawing was 40. The number of egg freezing cycles in the UK rose from 2,567 in 2019 to 6,932 in 2023 — a 45% jump just between 2022 and 2023 — though it still represents only around 7% of all UK fertility cycles.
A couple of specific points worth noting from the UK data:
Most women under 38 will have around 7 to 14 eggs collected in a single cycle.
Since 1 July 2022, UK law allows you to store eggs for up to 55 years, provided you renew your consent every 10 years. The laws are however different in different countries so you will want to consider what the local regulations are and what this means for your long term plans.
AMH and AFC: useful, but not crystal balls
When you're trying to work out your timing rather than the average woman's timing, two tests come up again and again: AMH and AFC. They're worth understanding properly, because they're often misunderstood:
AMH (Anti-Müllerian Hormone)
AMH is a hormone produced by the small follicles (egg sacs) developing in your ovaries. The level in your blood gives a reasonable indication of how many eggs you have left in reserve. It's helpful for egg freezing planning because it can guide your clinic on the dose of stimulation drugs and the likely number of eggs they'll retrieve.
But — and this is the bit that doesn't always get said clearly — AMH is not a good predictor of your chances of getting pregnant naturally. A low AMH does not mean you can't conceive; a high AMH does not mean you definitely will.
A few practical things:
AMH stays fairly stable across your menstrual cycle, so you can test on most days.
Hormonal contraception can lower AMH readings, so a result while you're on the pill, coil, or implant may not reflect your true level. Most clinics suggest waiting around three months after stopping (and please speak to your contraception provider before changing anything).
A result is read alongside an age-specific reference range, which your provider should explain to you.
If your AMH is lower than expected, please don't panic. It's one piece of a much bigger picture, and other tests will help you understand your fertility picture.
AFC (Antral Follicle Count)
AFC is the other half of the ovarian reserve picture. It's a vaginal ultrasound that physically counts the small follicles visible in your ovaries at the start of your cycle. A higher count points to more eggs available for stimulation.
AMH and AFC are usually used together — they're complementary, not competing tests. Neither tells you whether your eggs are good quality. Neither guarantees a pregnancy. What they do is help you and your doctor make a more informed plan.
The American Society for Reproductive Medicine has long cautioned against over-relying on ovarian reserve tests in isolation, especially home-test versions — they can produce results that look “falsely normal” or “falsely low” without proper clinical context so it is important to talk to a medical practitioner about this. If helpful you can speak to one of our Egg Advisors.
When medical reasons change the timing
For some women, the question isn't “when in life?” but “how soon can I do this?” — because a medical condition, or the treatment for one, may affect their fertility. In these situations, freezing eggs becomes part of preserving options before something changes like radiation therapy or hormone treatment.
Common medical reasons women in the UK consider egg freezing include:
Cancer treatment — chemotherapy and some radiotherapy can damage eggs. The NHS will generally consider funding egg freezing for fertility preservation in this situation, depending on where you live. Macmillan Cancer Support and Cancer Research UK both offer specific guidance on fertility preservation alongside treatment.
Endometriosis — the condition itself, and surgeries to treat it (especially on the ovaries), can reduce egg reserve over time. Recent research highlights that previous ovarian or endometriosis surgery is one of the factors that may affect what's possible during a freezing cycle.
PCOS (Polycystic Ovary Syndrome) — women with PCOS often have a higher AMH and a higher number of follicles, which can mean more eggs collected per cycle, but also a higher risk of ovarian hyperstimulation syndrome (OHSS). The cycle protocol usually needs to be adjusted carefully.
Autoimmune conditions — some autoimmune conditions, and certain treatments for them, can affect ovarian function. Timing here is best discussed with both your specialist and a fertility clinic together.
Premature ovarian insufficiency (POI) or a strong family history of early menopause — if your ovaries are likely to stop working earlier than average, an earlier conversation about freezing makes sense.
Gender-affirming care — eggs can be frozen before starting hormone therapy or surgical treatment that would affect fertility.
If any of these apply to you, please speak to both your treating doctor and a fertility specialist as early as possible.
“Age matters — but your personal fertility picture matters too”
We come back to this idea often at Egg Advisor, because it's the truest thing we can tell you: age is the strongest single factor, but it isn't the only one.
Two women the same age can have very different ovarian reserves. Two women with similar AMH levels can have very different lives, partners, finances, and goals. The “right” time to freeze is the one where the biology, your circumstances, and your own readiness line up well enough — not perfectly, but well enough.
A few things that genuinely help bring this picture into focus:
A consultation that includes both AMH and AFC, read in context with your age and any health history.
Honest conversations about your medical conditions, family history, and current treatments.
Lifestyle factors that influence egg quality. You can't increase the number of eggs you have, but smoking, heavy alcohol use, and being significantly under- or over-weight are known to negatively affect egg quality.
Time and space to think — without a marketing countdown clock pressing on you. UK regulators and bioethics bodies have specifically raised concerns about advertising that nudges women into urgent decisions.
What to do next
If you're still weighing this up, please don't feel you have to decide today. There are three sensible next steps, in any order:
Read the impartial sources first.
Get a baseline test. An AMH and AFC will give you data about your fertility, not the average woman's. Even if you decide not to freeze, knowing where you stand is valuable.
Talk to someone independent. That can be a fertility counsellor, your GP, or one of our Egg Advisors. We don't sell freezing, and we don't take referral fees from clinics — our job is to help you think clearly.
Whatever you choose, we hope this helped. Sign up for our newsletter for more information.
This article is for general guidance based on current UK practice and published evidence. It is not medical advice. Please discuss your individual situation with a registered fertility clinic or your GP.