Embryo Freezing
Embryo freezing is a full IVF cycle with the transfer left off the end. Up to the moment of fertilisation it is the same treatment as egg freezing. The same injections, the same scans, the same collection under sedation. Then the eggs meet sperm in a dish, whatever develops is grown on for about five days, and the embryos that make it are frozen. Everything that makes this a different decision happens after the fertilisation step, not before it.
Two things change. An embryo survives freezing and thawing more predictably than an egg does, and it tells you something an egg never can. How many actually fertilised, and how many of those kept going. That gives you a clear number you can count and plan around.
The trade is committing now to whose sperm it is. From the moment of fertilisation the embryos are shared, and using them later needs the other person's consent, which can be withdrawn. That is a legal point rather than a medical one, and talking it through early is what makes this a confident decision.
At a glance
- Also known as
- Embryo cryopreservation, blastocyst vitrification, freeze-all cycle
- Appointment time
- 15–30 minutes for the collection, after 10–14 days of injections
- Anaesthesia
- Sedation, occasionally general
- Time in clinic
- Day case
- Back to normal
- 1–2 days
- Whole process
- About 3 weeks from first injection to the freezing report
- Typical cost
- $12,000–$20,000 (United States, self-pay)
Figures reviewed .
On this page
Who it’s for
The clearest case is a couple with a reason to delay rather than treat. A cancer diagnosis, a posting abroad, surgery that will take the ovaries, or an IVF cycle that has produced more embryos than they want to transfer now. If you have sperm you are settled on, the extra information costs only the laboratory work, and you would be choosing eggs only for the flexibility.
Having no partner does not rule this out. Donor sperm is a legitimate route to embryos, and plenty of single women use it deliberately rather than as a fallback, because they know they would use a donor later anyway. If that is you, read the donor conception side of it first, since choosing a donor is the larger decision and it is not one to make inside a two-week cycle.
If the sperm question is genuinely open, eggs may suit you better. A partner you are unsure about, a relationship under strain, or a donor you have not chosen all point back to freezing eggs, which stay yours alone. The screening is the same either way, infectious disease bloods for both people before anything goes into shared storage, and clinics will want an ovarian reserve check before they quote you.
Before the injections start
Sit down with the other person and say out loud what you would each want to happen to the embryos if you were no longer together. Then ask the clinic to show you the form that records it. Doing it early means you sign it calmly, together, well before collection day.
How it’s done
The first fortnight is the egg freezing cycle, unchanged. Daily injections to grow a batch of follicles, a second drug to stop you ovulating early, three or four short scans, then a trigger injection at an exact time and collection about 36 hours later under sedation.
The lab work starts that afternoon. The mature eggs are either mixed with prepared sperm or injected one at a time by ICSI, which most clinics now use by default. The next morning you get the fertilisation number. It is almost always lower than the number of eggs collected, which is normal and expected.
What fertilised is then grown in an incubator for about five days, to the blastocyst stage. Not all of them get there, and the ones that do are the strongest. Blastocysts are graded on how the cells look, the ones judged usable are vitrified individually and stored, and the rest are not frozen. You come out of the cycle with a count of embryos and a grade for each one, which is the whole difference between this and freezing eggs.
On collection day
Ask the embryologist to report each figure separately as the week goes on. Eggs collected, eggs fertilised, and blastocysts frozen. Together they tell you much more about the cycle than the final count alone, and help plan any next step.
After embryo freezing
Physically this is the egg freezing recovery and nothing more. Bloating builds through the injection fortnight as the ovaries swell. Collection day means sedation, half an hour on the table, a couple of hours in recovery and someone else driving you home. Cramping like a heavy period for a day or two, some spotting, back to normal within the week.
The part that is specific to embryos is the waiting. You get a fertilisation report the morning after collection and then a week of daily lab updates before the final count, so plan something gentle for that week.
Watch for ovarian hyperstimulation in the days after collection. Rapid weight gain, a tight swollen abdomen, breathlessness or passing much less urine than usual all mean you ring the clinic that day rather than waiting.
| Days 1–10 | Injections start with your period. Scans and blood tests every few days. Bloating builds. |
|---|---|
| Day 10–12 | Final scan, then the trigger injection at an exact time, usually late at night. |
| Collection day | Collection under sedation, home a few hours later. Sperm sample given or frozen sample thawed. Consent forms signed. |
| Day after collection | The fertilisation number. Cramping, spotting and bloating at home. Watch for hyperstimulation symptoms. |
| Days 5–6 after | Blastocyst report. You learn how many embryos were good enough to freeze and how they graded. |
| Week 1–2 after | Back to normal activity. Ovaries settling. Storage contract and annual fee begin. |
| Years later | Thaw and transfer, as a separate treatment with its own fee, and a fresh consent check from both people. |
In the first week after collection
Decide where you want to be when the blastocyst call comes, and it should not be at your desk. The number usually narrows between the fertilisation report and the freezing report, and it is easier to take in somewhere comfortable.
Risks and complications
The cycle risks are the ones it shares with egg freezing. Ovarian hyperstimulation, severe in a small minority and much less common than it used to be. Bleeding, infection and damage to nearby structures at collection, all uncommon. Sedation carries its own small risk.
Then there is the outcome specific to fertilising now. Some cycles end with nothing frozen, because little fertilised or nothing reached blastocyst. That is hard on the day, and it is also valuable information to have now, while there is time to act on it.
The non-medical points are worth reading carefully. In most countries consent can be withdrawn by either person up to the point the embryos are used, so a relationship that ends can end the embryos too. Rules on use after a partner's death vary by country and often turn on a box ticked years earlier. Storage time limits differ as well, and they are set where the tank is, not where you live. Ask your clinic for the paperwork and check the rules where you are treated.
Embryo freezing results
Frozen blastocysts are robust. Modern vitrification loses only a small minority in the warming, with survival generally reported at ninety per cent or more. That is better than eggs and, more to the point, far more predictable, because a blastocyst has already proved it could get that far.
Live birth per embryo transferred is the figure that matters. Across frozen blastocyst transfers it runs at roughly a quarter to a third per attempt, and a good-quality blastocyst made in someone's early thirties sits at the top of that band rather than above it. It falls steadily from the late thirties onwards. Age when the embryo was made is the dominant variable. Age when you transfer it is nearly irrelevant, the same logic that makes freezing worth doing at all.
Grade is a modest predictor for one embryo and a reasonable one across a batch. Genetic testing of embryos, PGT-A, is offered widely and still debated. It sorts a batch more accurately rather than changing any embryo.
Ask the clinic for live birth per thawed embryo transfer, in your age band, rather than a pregnancy rate.
Alternatives to embryo freezing
Egg freezing is the real comparison, and it is closer than it might sound. Embryos give you better and more knowable numbers. Eggs give you sole control, no consent to renegotiate, and no need to answer the whose-sperm question at a point in your life when it may have no answer. Neither is the cautious option. They are cautious about different things.
Where people genuinely are in between, some clinics will fertilise half the batch and freeze the rest as eggs. It costs a little more, and it can be a good way to keep both options open. If the aim is a pregnancy now rather than later, a fresh IVF cycle is the same treatment without the storage.
Egg Freezing
A stimulation cycle that ends with eggs collected under sedation and frozen unfertilised, to be thawed and fertilised years later. Identical to the first half of IVF. Age at freezing sets the odds; the eggs do not age in storage.
Best for: anyone who wants children later, has no sperm source they want to commit to now, and would rather freeze at this age than at the next one
IVF
Conventional IVF, where the ovaries are stimulated to produce a batch of eggs, the eggs are collected under sedation and mixed with sperm in the laboratory, and one embryo is transferred. The core treatment that the other pages in this group are variations on.
Best for: anyone whose tubes, sperm or time make natural conception unlikely, and who wants the treatment with the best odds per attempt
Combining embryo freezing with other treatment
Most embryo freezing is not a separate treatment at all. It happens at the end of an IVF cycle, when more embryos develop than you transfer, and the surplus goes into storage. Some clinics now freeze everything by default and transfer in a later, unstimulated month, which gives the ovaries time to settle.
PGT-A, if you want it, has to be arranged before the cycle, because the biopsy happens at the blastocyst stage and the embryos are frozen while the results come back.
Embryo freezing cost
This is paid for in two stages, often years apart, so ask for both up front. The cycle now covers stimulation, collection, fertilisation, culture to day five and the freezing itself. Drugs are usually separate and swing most with your dose. ICSI, embryo glue, PGT-A and extended culture are all priced as extras, so check which are included in your quote.
Storage is billed annually and runs for as long as you keep the embryos. Then the second treatment, years later, is the thaw and transfer with its own scans and medication. Ask for a ten-year total rather than a cycle price, ask what a cancelled cycle costs when the response is poor, and ask what you are charged if nothing is good enough to freeze. Preservation before cancer treatment is funded in many public systems and by some insurers. Elective freezing rarely is, though some employers now cover part of it.
| Country | Self-pay | Public / insurance |
|---|---|---|
| United States Drugs typically $3,000–$6,000 extra; ICSI and PGT-A each add low thousands; storage roughly $500–$1,000 a year; thaw and transfer later around $4,000–$7,000 | $12,000–$20,000 | Often covered where state law mandates IVF benefits, or by an employer plan; elective preservation rarely |
| United Kingdom Drugs about £1,000–£2,000 extra; storage roughly £300–£500 a year; thaw and transfer later around £2,500–£4,000 | £5,000–£8,000 | NHS cycles include freezing of surplus embryos and a period of storage; elective preservation mainly self-pay |
| Thailand Usually quoted with drugs and ICSI; storage billed annually; allow two to three weeks in country for the cycle | $6,000–$10,000 | Self-pay for international patients |
Choosing a clinic for embryo freezing
Half of this is laboratory work, so judge the lab first. Ask for two figures: the proportion of collections that produce at least one frozen blastocyst, by age band, and the thaw survival rate for vitrified blastocysts. Blastocyst rates are the more telling figure, and a good lab will have them.
Then ask how they decide between conventional fertilisation and ICSI, and what happens to your embryos if the clinic is sold or closes. The question I would not skip is who walks you through the consent forms and when. The clinics I have most respected put that conversation in a separate appointment, before the drugs start, with both people in the room, and they say plainly that either of you can change your mind later.
At the consultation
Ask whether each blastocyst is frozen on its own, so that one can be thawed without the others. It sounds like a laboratory detail, and it decides whether a later transfer uses one embryo or puts two at risk to get it.
Clinics that do embryo freezing
Frequently asked questions
Are frozen embryos better than frozen eggs?
They survive thawing more predictably and they tell you how many actually developed. Eggs keep the decision and the control with you alone. See alternatives.
What happens to our embryos if we split up?
In most countries neither of you can use them without the other's consent, and either of you can withdraw it. The consent forms you sign before the cycle set out what follows. See risks.
Can I do this without a partner?
Yes, with donor sperm, and for many single women that is a deliberate choice rather than a compromise. Choosing the donor is the bigger decision. See who it's for.
How long can embryos stay frozen?
Limits are legal rather than biological, and they vary widely by country. Some allow renewals for decades, others cap storage at a few years. Check the law where the tank is.
Should we have the embryos genetically tested?
PGT-A can rank a batch more accurately, which helps most when there are several embryos. It is an add-on, still debated, and it ranks embryos rather than improving them. See results.