Egg freezing: What is frozen embryo transfer?

What is Egg freezing?

A frozen embryo transfer (FET) occurs when the cryopreserved embryos are thawed and transferred to the woman's uterus. Patients may request to freeze and store any additional embryos that are not used during their first cycle for various reasons. They may want a second child or their initial cycle will have failed. In some cases, their hormonal profile and / or their uterine lining is not optimal during a new IVF cycle. Before transferring the embryos, blood tests and ultrasounds are performed. This allows the doctor to identify the appropriate point in the patient's cycle to transfer the embryos. Some patients may need to take hormonal medications to prepare for the transfer.

Frozen embryo transfer (FET) with hormonal support-
For patients with irregular cycles and / or have time constraints, their doctor may recommend FET with hormonal support. In this case, hormones such as estrogen and progesterone are administered to suppress or control ovulation and to ensure that the patient's uterine lining is ready for transfer. The embryo transfer takes place on the third or fifth day of progesterone treatment. Know more about Embryo freezing success rate below.

Frozen embryo transfer (FET) by Natural Cycle
Cycles of FET, on the other hand, do not involve drugs that control ovulation, but are based on when ovulation occurs naturally. The patient's doctor closely monitors her menstrual cycle with blood tests and an ultrasound to determine the optimal day for embryo transfer. The frozen embryos are thawed and transferred to the uterus. Know more about egg freezing success rate below.

Vitrification: Cost to Egg freezing-
Until the rapid freezing process, called vitrification, was introduced a decade ago, frozen embryos had a very low implantation and live birth rate. There were various reasons for the low numbers. One of the main problems was the freezing process itself. The slow freezing method allowed ice crystals to form in the embryo, which damaged it to the point where it is no longer viable. Fortunately, with the development of vitrification, more than 90% of frozen embryos survive the thaw and have the same quality as fresh embryos. Vitrification consists of freezing eggs and embryos with extremely rapid cooling, too rapid to allow the formation of crystals.