Frozen embryo transfer in Greece: the protocol, the timetable and what to expect
Frozen embryo transfer in Greece: natural or assisted cycle, preparation from home, length of stay, cost, and what happens to any remaining embryos.
Read the articleFrozen embryo transfer: natural cycle or medicated cycle?
For a frozen embryo transfer, there are two main ways to prepare the uterus. The chances of success are similar. What sets them apart is the pregnancy that follows — and your travel plans.
When a patient returns to Greece for a frozen embryo transfer, the first practical question is: ‘When should I fly?’ The answer depends on how the endometrium is prepared. There are two main methods, with variations.
The natural cycle
Your own cycle is used. Ultrasound scans and hormone tests (LH, sometimes progesterone) identify the time of ovulation. The blastocyst is transferred approximately five to six days after ovulation, when the endometrium is naturally receptive. In the modified natural cycle, ovulation is triggered by an hCG injection once the follicle is mature, which allows the date to be set with slightly greater precision.
This approach requires regular cycles and spontaneous ovulation. It is not particularly suitable for PCOS or very irregular cycles.
The medicated (hormone replacement) cycle
The ovaries are put to rest and the cycle is reconstructed using hormones: oestrogen (tablets, patches or gel) for around two weeks, followed by an ultrasound scan to check the thickness of the endometrium, and then progesterone. The blastocyst is transferred on the sixth day of progesterone. There is no ovulation, so no corpus luteum: hormone treatment must be continued until approximately 10 to 12 weeks of pregnancy (see progesterone after a transfer).
Success rates
Randomised trials and recent meta-analyses show comparable birth rates between the two methods in women who ovulate normally. The choice is therefore not primarily based on success rates.
What sets them apart during pregnancy
Several large observational studies have shown that, following a frozen embryo transfer in a medicated cycle, there is a higher risk of hypertensive disorders of pregnancy, including pre-eclampsia, than following a transfer in a natural cycle. The explanation put forward is the absence of the corpus luteum, which produces substances other than progesterone. These findings have led many teams to favour the natural cycle where possible, particularly in women already at risk — such as those of advanced age, with high blood pressure, or undergoing egg donation. The subject remains a matter of debate; this is a question to put to your doctor.
How they differ in terms of organisation
| Natural cycle | Medicated cycle | |
|---|---|---|
| Date of transfer | Known a few days in advance | Can be scheduled weeks in advance |
| Monitoring | Several ultrasound scans and blood tests around the time of ovulation | Usually one ultrasound scan before progesterone |
| Medication | Minimal (trigger, light support) | Oestrogen and progesterone up to 10–12 weeks |
| Flight tickets | Flexible booking essential | Can be booked early |
| Possible cancellation | If ovulation is not clearly identified | If the endometrium remains too thin |
For a patient coming from abroad, the medicated cycle therefore offers a real practical advantage: the transfer date is set and the flight is booked. The natural cycle requires more coordination, but it is entirely feasible: follow-up scans are carried out at home, by your own gynaecologist, who sends the results to the Greek clinic. As soon as ovulation is detected or triggered, the transfer date is set and you fly out two or three days beforehand. The stay in Greece is then very short.
How I organise it
I put your gynaecologist in touch with the clinic before the cycle begins, with a written protocol in English: which tests, on which days, and to whom the results should be sent. I recommend a flexible flight ticket and accommodation that can be booked at the last minute (see the budget for your stay in Thessaloniki). And if your endometrium is usually thin, the decision is discussed differently: see thin endometrium and IVF.
Frequently asked questions
Natural or medicated cycle: which offers the best chances?
In women who ovulate normally, randomised trials show comparable birth rates between the two methods.
Why do some doctors prefer the natural cycle?
Because several observational studies link the medicated cycle, which lacks a corpus luteum, to a higher risk of pre-eclampsia and hypertensive disorders during pregnancy.
Which cycle is the simplest for those coming from abroad?
The medicated cycle, as the date can be scheduled in advance. The natural cycle remains feasible with ultrasound monitoring in your home country and a flexible ticket.
How long should you take the hormones after a frozen embryo transfer in a medicated cycle?
Oestrogen and progesterone are generally continued until 10 to 12 weeks of pregnancy, depending on the clinic’s protocol.
Sources
- Ghobara T, Gelbaya TA, Ayeleke RO, ‘Cycle regimens for frozen-thawed embryo transfer’, Cochrane Database of Systematic Reviews, 2017.
- Saito K et al., ‘Endometrial preparation methods for frozen-thawed embryo transfer are associated with altered risks of hypertensive disorders of pregnancy, placenta accreta, and gestational diabetes mellitus’, Human Reproduction, 2019.
- von Versen-Höynck F et al., ‘Increased preeclampsia risk and reduced aortic compliance with in vitro fertilization cycles in the absence of a corpus luteum’, Hypertension, 2019.
This article provides general practical and administrative information. It does not constitute medical or legal advice. Rules and costs are subject to change: always check for the latest information with your health insurance provider, the clinic treating you and your doctor.
Triada Baloukoudis
Independent IVF patient coordinator in Thessaloniki, with 24 years of experience supporting patients travelling from abroad. More · Contact · Facebook
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