Recent advances in IVF laboratory methods have allowed for the successful culture of embryos to the blastocyst stage. Blastocysts may have a better potential to implant into the uterine wall than earlier stage embryos.
Many embryos stop growing at the four- to eight-cell stage, probably because of some inherent problem. Therefore, fewer embryos will have the ability to grow to the blastocyst stage. Those that successfully reach the blastocyst stage are probably more developmentally competent than earlier stage embryos. As well, their stage of development when replaced into the uterus is very similar to what it would be in a natural conception cycle.
Step-by-Step Process
How Frozen blastocysts (Embryo Transfer) Works?
Embryo Creation
Fresh embryos are created in a lab using IVF, where eggs are fertilized by sperm.
Cryopreservation
The embryos will be treated with cryoprotectants that prevent ice crystal formation. Then, they are frozen and stored at a temperature of -196°C in liquid nitrogen.
Embryos’ Storage
The embryos are then stored in safe cryogenic tanks until they are ready for use.
Thawed embryos & Transfer
When you're ready to proceed with pregnancy, the embryos are then thawed and transferred to the uterus during carefully chosen periods of time.