Short answer
Egg freezing can keep some of your eggs at the quality they had when they were collected, but it cannot promise a future baby. The single biggest factor is your age when the eggs are frozen: eggs frozen younger, particularly before 35, give a better chance of success than eggs frozen later. It involves the same hormone stimulation and egg collection as IVF, and far fewer people come back to use their eggs than freeze them.
Key points
- The stimulation and collection process usually takes around two to three weeks.
- Age at freezing matters much more than age when the eggs are later thawed.
- Thawed eggs have to be fertilised with ICSI (sperm injected directly into each egg).
- In the UK, eggs can be stored for up to 55 years, but consent must be renewed every 10 years.
- Guidelines say the evidence for predicting an individual’s chance of a live birth is limited.
What egg freezing involves
Egg freezing (oocyte cryopreservation) uses the first half of IVF. Hormone medicines stimulate the ovaries to mature several eggs at once, and the eggs are then collected under sedation or general anaesthetic. The UK fertility regulator, the Human Fertilisation and Embryology Authority (HFEA), says this usually takes around two to three weeks.1
The eggs are then frozen, now usually by vitrification (very rapid freezing that avoids ice crystals). The HFEA notes that vitrification is more successful than the older slow-cooling method.1 The European Society of Human Reproduction and Embryology (ESHRE) describes egg freezing as the method of choice for age-related fertility preservation since vitrification became available.4
When the eggs are used later, they are thawed and fertilised in the laboratory. Freezing toughens the egg’s outer coat, so fertilisation is done by intracytoplasmic sperm injection (ICSI) rather than standard IVF.1 Any resulting embryo is then transferred to the womb.
Why age at freezing matters most
The number and quality of eggs both fall with age, which is why natural fertility declines. Freezing aims to preserve eggs at the quality they had on the day of collection.1 It cannot improve eggs that have already been affected by age.
An HFEA report found that age at freezing affected success, whereas age at thaw had relatively little impact. The regulator’s chair said that freezing below 35 offers the best chance.3 The American Society for Reproductive Medicine (ASRM) guideline reaches a similar conclusion: live birth rates per embryo transfer appear better when eggs are frozen at a younger age, though it grades this evidence as weak.5
Ovarian reserve (how many eggs remain) also affects how many eggs one cycle yields. The HFEA says most patients under 38 have around 7 to 14 eggs collected, though this is not always possible when reserve is low.1 Some people need more than one cycle to store the number of eggs their clinician suggests.
What are the chances of success?
Honest answer: hard to predict for any individual. The ASRM guideline states that there is insufficient evidence to counsel women about the likelihood of live birth after planned egg freezing.5 The evidence for precise personal estimates is therefore Limited.
UK data give a rough picture. In 2016, the birth rate per treatment cycle using a person’s own thawed eggs was about 18%, up from 12% in 2014.3 These figures pool people of all ages and are now several years old. The HFEA warns that older egg-freezing data are not directly comparable with current results because the technique has improved.1
Another reason reliable figures are scarce is that relatively few people come back to use their eggs. The HFEA says far fewer return than freeze, and in 2023 the average age at freezing was 35 while the average age at thawing was 40.2
| Factor | What is known |
|---|---|
| Age at freezing | The main factor; younger is better35 |
| Age at thaw | Relatively little effect on chances, according to HFEA data3 |
| Freezing method | Vitrification more successful than slow cooling1 |
| Number of eggs stored | Depends on ovarian reserve; often 7 to 14 per cycle under 381 |
| Individual prediction | Evidence described as insufficient by ASRM5 |
What are the risks?
The HFEA describes the process as mostly very safe. Side effects of the hormone medicines are usually mild, but in rare cases ovarian hyperstimulation syndrome (OHSS, an over-response of the ovaries) can be serious and, in extreme cases, potentially fatal.1 Egg collection is a minor procedure but still carries the usual small risks of a needle procedure under sedation.
The HFEA is also clear that the major risk is simply that it will not work.1 ESHRE recommends that anyone considering egg freezing for age-related fertility loss be fully informed about success rates, risks, benefits, costs and possible long-term physical and psychological consequences.4
Information on pregnancies from planned egg freezing is still limited. The ASRM guideline notes that neonatal outcomes after using previously frozen eggs appear similar to those after fresh eggs, but this is based on a small number of births.5
How long can eggs be stored?
In the UK, rules changed on 1 July 2022. Eggs can now be stored for up to 55 years from when they were first frozen, but consent must be renewed every 10 years.1 If consent is not renewed, or the clinic cannot make contact, the eggs may be removed from storage and disposed of.1
Storage law differs between countries, so anyone freezing eggs abroad should check the local limits and how they would move eggs later. Our page on how fertility laws differ between countries covers this.
Common questions
Is egg freezing becoming more common?
Yes, in the UK egg freezing cycles rose from 2,567 in 2019 to 6,932 in 2023.2 The HFEA estimates that at least 15% of egg freezing cycles from 2018 to 2022 were for medical reasons, such as before cancer treatment.2
Does an AMH test tell me whether to freeze my eggs?
Not on its own; it mainly helps estimate how many eggs a cycle might yield. See what an AMH test tells you for what it can and cannot show.
Can I freeze eggs after 40?
It may be possible, but success is lower because age at freezing is the main factor.3 ESHRE advises that suitability should be judged case by case rather than by a fixed age cut-off.4
How should I compare clinics’ success figures?
Cautiously, because frozen-egg data are limited. The HFEA suggests also looking at a clinic’s fresh IVF success rates for patients using their own eggs in your age band.1
Bottom line
Egg freezing is an option for preserving some fertility, not a promise of a future pregnancy. Age at freezing shapes the odds more than anything else, and personal predictions remain uncertain, so it helps to go in with realistic expectations and a clear view of the storage rules.
Related reading
- Fertility treatment overview
- What does an AMH test tell you?
- What is ovarian hyperstimulation syndrome (OHSS)?
- What is ICSI?
- How does age affect IVF success?
Sources
- Human Fertilisation and Embryology Authority. Egg freezing. HFEA. https://www.hfea.gov.uk/treatments/fertility-preservation/egg-freezing/. Accessed 5 November 2026.
- Human Fertilisation and Embryology Authority. Egg freezing: a factsheet. HFEA. https://www.hfea.gov.uk/about-us/media-centre/egg-freezing-a-factsheet/. Accessed 5 November 2026.
- Human Fertilisation and Embryology Authority. Age is the key factor for egg freezing success says new HFEA report, as overall treatment numbers remain low. HFEA; 2018. https://hfea.gov.uk/about-us/news-and-press-releases/2018/press-release-age-is-the-key-factor-for-egg-freezing-success-says-new-hfea-report-as-overall-treatment-numbers-remain-low/. Accessed 5 November 2026.
- ESHRE Guideline Group on Female Fertility Preservation; Anderson RA, et al. ESHRE guideline: female fertility preservation. Human Reproduction Open; 2020:hoaa052. doi:10.1093/hropen/hoaa052. https://academic.oup.com/hropen/article/2020/4/hoaa052/5981739
- Practice Committee of the American Society for Reproductive Medicine. Evidence-based outcomes after oocyte cryopreservation for donor oocyte in vitro fertilization and planned oocyte cryopreservation: a guideline. Fertility and Sterility; 2021;116:36–47. https://www.asrm.org/practice-guidance/practice-committee-documents/evidence-based-outcomes-after-oocyte-cryopreservation-for-donor-oocyte-in-vitro-fertilization-and-planned-oocyte-cryopreservation-a-guideline-2021. Accessed 5 November 2026.
Article history
- — First published.