Healthy embryos resulting from an IVF cycle but not transferred to the patient at the end of the cycle can be cryopreserved and stored. If the initial treatment was unsuccessful and you have excess embryos frozen, you may undergo a FET about 2 months later. There is also a trend to “freeze all” the embryos in the fresh cycle and then transferring the frozen embryos later when the womb lining is more receptive.
There are a few protocols for the FET. The focus of the FET cycle is to build an optimal uterine lining and to identify the appropriate point in the patient’s cycle to transfer the embryos. In natural cycle FET, the doctor scans the patient frequently to identify ovulation and the embryos are transferred after the patient is given some progesterone. Some FET patients may also take hormone medications to prepare for the transfer. The medication prescribed is to keep your ovaries from ovulating during your cycle as ovulation causes the uterine environment to change, preventing accurate synchronization of your uterus with your embryos. The embryo transfer procedure is the same as the IVF procedure.