Frozen Embryo Transfer (FET)
What is a Frozen Embryo Transfer?
Frozen embryo Transfer (FET) is the transfer of frozen embryos that have been vitrified in an earlier procedure.
Following IVF treatment, many couples choose to freeze their spare embryos for use at a later stage. The technique of freezing embryos allows couples to use these embryos should their first attempt at achieving pregnancy from IVF fail, or if they would like to have more children in the future.
Natural cycle: A frozen embryo transfer can be performed in either stimulated or unstimulated cycles. During an unstimulated natural cycle, the embryo(s) are replaced when implantation is most likely.
Stimulated cycle: With a stimulated cycle, you will need to take medication to go through the process of down-regulation. This temporarily shuts down your ovaries and prevents any eggs from being released. You will have a scan on day two or three of your period and start taking medication to prepare your womb for the embryo transfer. A second ultrasound scan at day twelve or so will be performed to check the thickness of your endometrium. Once it is of the appropriate thickness, progesterone is introduced for five days and then we can start the embryo thawing process and book your transfer.
Embryo thawing: Our embryology team will inform you of how well your embryos have survived the thawing process and if they are of good enough quality for your transfer to take place. Sometimes embryos do not survive the thawing process. If this happens, we will book you a review appointment with your doctor to discuss your options going forward. Freezing is complex and you should bear in mind that success rates can be reduced with frozen embryo transfer.
Embryo transfer: The embryo transfer is similar to a smear test. It may cause some minimal discomfort. The culture medium containing one or two embryos is loaded into a thin catheter with a syringe on the end. The doctor carefully guides the catheter through the vagina and cervix, and deposits the embryo(s) into the uterus. Implantation begins three to four days later.