Physiological receptivity
Frozen Embryo Transfer (FET)
Transfer of a cryopreserved blastocyst into an optimally prepared natural or hormone-synchronised endometrium.
Quick facts
- Category
- Embryo transfer cycle
- Duration
- 18 to 22 days of endometrial preparation
- Egg retrieval
- Not required — embryos are already stored
- Laboratory
- Controlled warming and re-expansion assessment
- Sedation
- None — a 10-minute procedure
- Follow-up
- Progesterone support, then a pregnancy test
Clinical overview
Understanding Frozen Embryo Transfer
In traditional fresh IVF, embryos are transferred just days after intensive ovarian stimulation, when oestrogen levels are supra-physiological. Frozen Embryo Transfer (FET) decouples the egg retrieval from the transfer. High-grade blastocysts are vitrified, giving the body time to rest and allowing our clinical team to prepare the endometrium under optimal hormonal synchronisation.
Is this pathway likely to be relevant for you?
Situations in which a specialist may suggest discussing this treatment:
- Patients who banked embryos during an IVF cycle to avoid OHSS
- Couples doing Preimplantation Genetic Testing (PGT-A) who awaited screening results
Step by step
What actually happens, stage by stage
Knowing the sequence in advance removes a great deal of anxiety. Timings are typical rather than fixed, and yours will be confirmed by your specialist.
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Cycle baseline scan
Day 2 check · Day 2/3
Pelvic ultrasound confirms quiet ovaries and a thin, reset baseline endometrial lining.
-
Endometrial priming
Oestrogen phase · 10–14 days
Oral oestradiol tablets taken for 10 to 14 days gently build a trilaminar uterine lining.
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Lining assessment scan
Target above 7.5mm · Day 12–14
Ultrasound measures endometrial thickness and checks for the triple-line pattern.
-
Progesterone initiation
Window of implantation · 5 days before transfer
Progesterone administration begins, opening the receptive window for blastocyst attachment.
-
Blastocyst thawing
Embryology laboratory · Morning of transfer
The chosen embryo is rapidly warmed from −196°C and evaluated for cellular re-expansion.
-
Ultrasound-guided transfer
Comfortable placement · 10 minutes
Under abdominal ultrasound, the re-expanded blastocyst is gently delivered to the uterine fundus.
Questions answered
Frequently asked about Frozen Embryo Transfer
No. Modern vitrification, or flash-freezing, prevents ice crystal formation. Clinical studies show FET cycles often have higher implantation rates than fresh cycles, because the endometrium has not been exposed to high stimulation hormones.
Next step
Discuss Frozen Embryo Transfer with a fertility specialist
A quiet, confidential consultation in Mysuru, or a video teleconsultation if travelling is difficult. Bring any previous reports — we will go through them with you.