Spare embryos from your IVF treatment can be frozen for future use, depending on their quality and also embryos resulting from an IVF cycle but not transfer at the end of the cycle can be cryopreserved and stored.
When the patient is ready to have another child, her embryo(s) are thawed and transferred to her uterus at the appropriate point in her menstrual cycle. This process is called a frozen embryo transfer (FET).
A patient preparing for an FET has blood testing and ultrasound scans that enable to identify the appropriate point in the patient’s cycle to transfer the embryo(s). Some FET patients may also take hormone medication to prepare for the transfer.
FETs have high success rates and do not require a full IVF cycle.
Some patients may also undergo “natural” frozen embryo transfers, which require less or no hormone supplementation.
The FET 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.
With a medicated 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 eight or nine will be performed to check the thickness of your endometrium. Once it is of the appropriate thickness we can start the embryo thawing process and transfer.
The embryo transfer is similar to a smear test. It may cause some minimal discomfort. The culture medium containing two or three embryos is loaded into a thin catheter with a syringe on the end.
The catheter carefully guides through the vagina and cervix, and deposits the embryo(s) into the uterus.