Frozen Embryo Transfer (FET)
FET is the thawing of a previously frozen embryo and its transfer to the uterus in a suitable cycle, allowing the uterine environment to be prepared.
Frozen Embryo Transfer (FET) — At a Glance
Frozen embryo transfer (FET) thaws a vitrified embryo from an earlier IVF cycle and places it in the uterus once the lining is optimally prepared. Because timing can be controlled, FET is a flexible, safe and increasingly common part of modern IVF.
- What it is: a previously frozen embryo is warmed and transferred in a prepared cycle.
- Why it's used: to synchronise the uterine lining, avoid OHSS, follow PGT, and support “freeze-all” plans.
- Two approaches: a natural cycle or a medicated (hormone-supported) cycle.
- Timing: the transfer day is set by when progesterone starts and the embryo's stage.
- Is it painful? The transfer uses a thin catheter — usually painless, with no anaesthetic.
- After: mild cramping/spotting can occur; only a beta-hCG test confirms the result.
- Cost: depends on your plan; you receive a personalised quote after assessment.
Why is FET preferred?
Frozen transfer allows the uterine lining to be prepared at the optimal time, surplus embryos to be used, and planning after PGT.
- Preparing the uterine lining at the right time
- Preserving surplus embryos
- Planning after PGT
- Flexible treatment timing
How is FET performed?
After the uterine lining is suitably prepared, the frozen embryo is thawed and transferred. The procedure is usually short and comfortable.
Timing and preparation are planned individually by your physician.
Fresh or Frozen Transfer?
In some cases a frozen transfer is preferred so the uterine lining can be prepared more optimally.
The most suitable approach is determined by your physician based on your treatment response.
What Is Frozen Embryo Transfer (FET)?
Frozen embryo transfer (FET) is the thawing of a previously frozen embryo and its transfer to the uterus in a suitable cycle. This approach allows the uterine lining to be prepared at the optimal time.
FET allows surplus, good-quality embryos obtained during IVF to be used, so a single egg retrieval can offer more than one transfer opportunity.
Why Is FET Preferred?
Frozen transfer allows the uterine lining to be prepared at the right time, planning after PGT, and in some cases improved safety (for example, a freeze-all strategy when there is OHSS risk). It also provides flexible timing.
How Is the Endometrium Prepared?
Before FET, the uterine lining (endometrium) is prepared to a suitable thickness and structure through natural cycle tracking or hormonal support. Preparation and timing are planned individually by your physician.
How Is the Procedure Done?
When the endometrium is suitably prepared, the frozen embryo is thawed and transferred into the uterus with a thin catheter. The procedure is short and usually painless; it requires no anesthesia. Prolonged bed rest is not needed afterwards.
Comparison With Fresh Transfer
In a fresh transfer, the embryo is transferred in the same cycle as retrieval; in FET, the frozen embryo is transferred in a later cycle. Which approach is appropriate is determined by your medical situation, embryo status and treatment response.
The Health of Frozen Embryos
Vitrification provides high survival; suitable embryos are transferred after thawing. The freezing and thawing process is carried out carefully by an experienced embryology team.
The Post-Transfer Period
Progesterone support is usually given after transfer, and the pregnancy test is done about 10-12 days later. We cover what to pay attention to during this period in detail in our blog articles.
Frequently Asked Questions
Is FET better than fresh transfer? It depends on the situation; it can be an advantage in some patients. Are frozen embryos healthy? Vitrification provides high survival. Is FET painful? The procedure is short and usually comfortable.
You can contact us to evaluate the most suitable transfer approach for you.
What Is Frozen Embryo Transfer?
Frozen embryo transfer (FET) warms an embryo that was created and vitrified in an earlier IVF cycle, and places it in the uterus during a carefully prepared cycle.
Thanks to modern vitrification, embryo survival on warming is very high. This means good-quality embryos not used in the first transfer can be stored safely and used later in a separate, well-prepared cycle. It also means a fresh transfer can be deliberately postponed when that gives a better chance — for example to let the body recover after stimulation, or to await genetic-test results.
FET is now a routine part of IVF and, in many situations, gives more control over timing than a fresh transfer. See our guide on blastocyst transfer and embryo grading for more.
Vitrification freezes the embryo so rapidly that damaging ice crystals do not form, which is why survival on warming is now very high. In practice this means a single egg-retrieval cycle can yield several good embryos: those not used in the first transfer are stored and can be used in later, well-timed cycles — without repeating stimulation and retrieval.
Why Choose a Frozen Transfer?
There are several reasons FET may be preferred:
- Endometrial synchronisation: the transfer happens when the lining is at its best.
- Avoiding OHSS: if the risk after stimulation is high, embryos are frozen and transferred later (freeze-all).
- After PGT: genetically tested embryos are frozen while results are awaited.
- Flexibility: the transfer can be planned for the best time for you and your uterus.
Being able to store good embryos also means one egg-retrieval cycle can provide more than one chance at transfer. This spares you from repeating stimulation and retrieval, and lets each transfer be planned for the most favourable moment — an approach that is both gentler and, in many cases, more effective.
Fresh vs Frozen Embryo Transfer
Both approaches have their place; the choice depends on embryo status, the uterine environment and your medical situation.
| Feature | Fresh transfer | Frozen transfer (FET) |
|---|---|---|
| Timing | Same cycle as retrieval | A separate, prepared cycle |
| Uterine lining | Can be affected by stimulation | Prepared more controllably |
| OHSS risk | Higher in some cases | Reduced with freeze-all |
| Fits with PGT | Must wait for results | Planned after results |
This decision is fully individual; your specialist recommends the path that gives you the best chance.
The FET Process
FET begins by preparing the uterine lining. There are two main approaches: a natural cycle and a medicated (hormone-supported) cycle.
Cycle planning
Your specialist chooses a natural or medicated cycle for you.
Endometrial preparation
Ultrasound tracks lining thickness and pattern; a medicated cycle adds estrogen support.
Progesterone start
When the lining is ready, progesterone begins; the transfer day is set from this.
Warming the embryo
On transfer day the embryo is warmed in the laboratory and its viability checked.
Transfer
The embryo is placed in the uterus with a thin, soft catheter under ultrasound guidance (~10 min, usually painless).
hCG blood test
About 9–12 days after transfer, a blood test confirms pregnancy.
Natural vs Medicated Cycle — and When FET Is Done
The transfer day depends on the cycle type and the day the embryo was frozen. The table compares the two approaches.
| Approach | How the lining is prepared | Transfer timing |
|---|---|---|
| Natural cycle | Your own ovulation is tracked (ultrasound/blood) | After ovulation, based on the embryo's stage |
| Medicated (hormone) cycle | Estrogen prepares the lining, then progesterone starts | Set from progesterone start (e.g. ~day 5 for a blastocyst) |
There is no single fixed “cycle day” for FET; in a medicated cycle estrogen usually starts in the first days of the period, and the transfer is timed from progesterone. Your exact schedule is set individually with ultrasound monitoring.
After a Frozen Embryo Transfer
Mild symptoms can occur after transfer; most are normal and do not, on their own, indicate the result.
| Common (usually normal) | Advice |
|---|---|
| Mild cramping | Take prescribed medication (progesterone) regularly |
| Light spotting | Avoid heavy exertion and excessive heat |
| Bloating, tenderness | Eat well and stay hydrated |
| No symptoms at all | Don't worry; wait for the beta-hCG test |
Only a beta-hCG blood test confirms the result. For more, see implantation symptoms after transfer and hCG levels in early pregnancy. Contact your doctor for severe pain or heavy bleeding.
What Affects FET Success?
FET success reflects several factors and varies from person to person.
| Factor | Effect |
|---|---|
| Embryo quality | Good blastocyst-stage embryos improve implantation chances |
| Endometrial lining | Adequate thickness and pattern are important |
| Progesterone timing | Correct synchronisation of embryo and lining |
| Number transferred | Single embryo transfer (SET) lowers the risk of twins |
With modern vitrification, frozen-transfer outcomes are close to fresh, and in some situations FET has an advantage. Because some factors (such as embryo quality and your age at the time the embryo was created) cannot be changed, we focus on optimising what can be controlled — lining preparation, progesterone timing and the number of embryos transferred — for your specific situation.
It is also worth remembering that success is usually best measured across a full course of treatment rather than a single transfer. Because one retrieval can produce several frozen embryos, a freeze-all strategy often gives more than one opportunity from the same cycle — which is why cumulative outcomes, not a one-off figure, are the most meaningful way to think about your chances.
What Affects the Cost of FET?
The cost of FET depends on your plan. Here are the factors that shape it:
- The cycle type (natural or medicated) and medications
- Embryo warming and laboratory work
- The number of ultrasound and hormone checks
- Any embryo storage and renewal fees
Who Is Frozen Embryo Transfer For?
FET comes up in many IVF scenarios. Common situations include:
| Situation | Why FET? |
|---|---|
| Freeze-all | Fresh transfer is postponed due to OHSS risk or hormone levels |
| After PGT | Embryos are frozen while genetic-test results are awaited |
| Remaining good embryos | A new transfer using embryos stored from a previous cycle |
| Sub-optimal uterine timing | Transfer is planned once the endometrium is ready |
Suitability is assessed from the status of your embryos and your uterine environment.
Endometrial Preparation and Progesterone
A successful transfer needs a uterine lining of adequate thickness and pattern, with progesterone support starting at the right time.
In a medicated cycle, estrogen first thickens the endometrium; once it is ready, progesterone is added and the transfer is timed accordingly. Target progesterone levels vary between people and protocols, so your doctor sets your medication plan individually.
Before transfer, a balanced diet, avoiding smoking and alcohol, and taking prescribed medication regularly are usually advised. See our guide on follow-up care after IVF for more.
Frequently Searched Questions
| Soru / Question | Kısa yanıt / Quick answer |
|---|---|
| When is a frozen embryo transfer done? | When the uterine lining is ready; in a medicated cycle it is timed from the progesterone start and the embryo's stage. |
| Is FET as successful as a fresh transfer? | With modern vitrification, outcomes are close to fresh transfer, and FET has advantages in some cases. |
| Is cramping after transfer normal? | Mild cramping and spotting are common and usually normal; contact your doctor for severe pain. |
| Does transferring 2 embryos improve success? | The number transferred is weighed against the risk of twins; single embryo transfer (SET) is often recommended. |
| Natural or medicated cycle — which is better? | It depends on your cycle and lining; your specialist recommends the most suitable approach. |
| How many days after progesterone is a blastocyst transferred? | Usually about 5 days after progesterone starts, matching the embryo's day-5 stage; exact timing is individual. |
| Do I need to be in Turkey for the whole FET cycle? | Much of the monitoring can be arranged efficiently; we plan your visit timing around the transfer in advance. |
Why Op. Dr. Ali İhsan Gönenç?
FET success depends on precise timing and a well-prepared uterine environment. Here, the process is planned individually under the close monitoring of one specialist.
- Single-consultant continuity and careful endometrial monitoring
- Modern vitrification laboratory at Medical Park Bahçelievler
- Transparent, pressure-free guidance
Contact us to arrange an assessment consultation.
Op. Dr. Ali İhsan Gönenç
Obstetrics & Gynecology · IVF — Medical Park Bahçelievler IVF Center
Op. Dr. Ali İhsan Gönenç is an experienced obstetrician and gynecologist focused on infertility and IVF. The medical information on this page has been reviewed by him for accuracy.
View Doctor Profile →Sources: ASRM — ReproductiveFacts · Mayo Clinic — IVF
Frequently Asked Questions
Common questions, clearly answered.
✓ Medical content reviewed by Op. Dr. Ali İhsan Gönenç · Last updated: July 2026
Vitrification provides high survival; suitable embryos are transferred after thawing.
It depends on the situation; your physician recommends the best approach for you.
FET is the transfer of a previously frozen embryo, after thawing, into a prepared uterus. It allows the use of good-quality embryos remaining from earlier cycles.
The frozen embryo is thawed, the uterine lining is prepared in a natural or medicated cycle, and the embryo is placed into the uterus with a thin catheter on the appropriate day.
The transfer day depends on how the uterine lining is prepared and the cycle type, so it varies from person to person. The correct timing is planned during monitoring.
The thickness of the uterine lining and hormone levels are monitored with ultrasound and blood tests. Transfer is planned once suitable conditions are reached.
Both can be successful in the right situations; the choice depends on the patient's medical condition. In some cases a frozen transfer is more suitable.
With modern vitrification, the large majority of embryos survive thawing and remain healthy. The process is carried out by an experienced embryology team.
You can usually return to normal daily life while avoiding heavy exertion and any medication not advised by your doctor. Prescribed medications should be used regularly.
The pregnancy test is usually done about two weeks after the transfer, on the date your doctor specifies. Testing too early can give misleading results.
Book your consultation with Op. Dr. Ali İhsan Gönenç
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