Dr. Shilpa G B

Best FET Centre in Bangalore

A Frozen Embryo Transfer (FET) is a type of fertility treatment in which embryos created during a previous IVF cycle are frozen and stored (cryopreservation). Thawed cryopreserved embryos are then implanted in a woman’s uterus to help her conceive a child.
When it comes to the history of FET, cryopreservation has been around for a very long time. Earlier techniques of egg storage were ineffective because they caused excessive solidification as a result of the formation of an ice coating on the embryo, making it unproductive.
Cryopreserved embryos have seen tremendous improvements in recent years, thanks to new developments such as vitrification, which is a rapid freezing procedure that has dramatically enhanced the outcomes.

How are the Embryos Frozen?

The major goal of freezing embryos is to keep them safe for future use in other procedures. In the future, the freezing of excess embryos created in a new IVF cycle will serve as the foundation for FET therapy in the future. As a result, it is critical to understand the procedure of freezing embryos before proceeding.
Embryos may be solidified from the second day (four cell stage) through the fifth day (blastocyst stage). A cryoprotectant is employed in the process of cryopreservation. This cryoprotectant substitutes the water that would otherwise be present within the cells. At this point, the embryologist allows the embryos to develop in cryoprotectant before hardening them on a petri dish. As soon as most of the water contained inside the cell has been ejected, the embryologist chills the embryo till it reaches its preserved stage.
There are two ways of freezing available for this purpose:
  • Slow Freezing:During slow freezing, the embryos are put in cylinders that are tightly sealed. Afterwards, the temperature is progressively lowered to a comfortable level. This helps to prevent the aging of embryos and reduces the risk of harm to the embryos throughout the developmental process. Anyhow, there are some disadvantages to this procedure. Slow freezing takes a long time to complete. Aside from that, the equipment required for slow freezing are costly, contributing to the overall high cost of the procedure.
  •  
  • Vitrification: It is often considered an advanced cryopreservation procedure. In this method, the embryologist hardens the cryoprotected embryos in such a short period of time that the odds of water solidifying inside the cell are almost non-existent. Defrosting embryos before the FET procedure helps to safeguard them and increase their chances of survival. When the process of solidification or freezing is complete, the embryos are placed in tanks filled with liquid nitrogen that helps maintain a consistent temperature of -196° Celsius. Furthermore, patients who have an excess of good quality embryos in addition to the embryos chosen for transfer can have them vitrified to increase their chances of having a baby in subsequent embryo transfers without having to go through a fresh stimulation cycle.