Frozen Embryo Transfer

What is a Frozen Embryo Transfer (FET)?

A Frozen Embryo Transfer involves the use of embryos that were cryopreserved during a previous In Vitro Fertilization (IVF) or donor egg cycle. These embryos are thawed and transferred into the uterus, offering an opportunity for pregnancy without undergoing a full IVF cycle again.

Reasons for Opting for an FET

Medical Consideration: In an IVF cycle, the body undergoes controlled ovarian hyperstimulation, which can place significant stress on the body. Sometimes, the conditions for a fresh embryo transfer are not optimal due to hormonal imbalances or suboptimal endometrial lining. In such instances, transitioning to a frozen transfer is advised for better implantation potential.

Planning Convenience: For many, especially those traveling for treatment, FET cycles provide a logistical advantage. They are less likely to be canceled, can be scheduled with greater certainty, and maintain similar success rates to fresh transfers.
Utilization of Surplus Embryos: Standard IVF often results in multiple embryos. The practice now leans towards transferring one or two embryos and freezing the rest for future use, whether for subsequent pregnancy attempts or expanding the family later.

The FET Process Explained

Preparation and Expectations: An FET cycle is tailored to each individual, with the procedure varying based on medication response. A typical medicated FET cycle involves:

• Uterine Lining Enhancement: Estrogen supplementation is the initial step, aiming to thicken the uterine lining as it would naturally during a menstrual cycle.
• Lining Receptivity: After a lining check, the estrogen regimen continues, with progesterone introduced to improve the lining’s receptivity to the embryo. The timing of progesterone administration dictates the embryo transfer schedule:
  
  • Day 3 embryos (cleavage stage) are transferred four days post-progesterone initiation.
  • Day 5 embryos (blastocyst stage) are transferred six days after starting progesterone.

The Transfer Procedure: An FET is straightforward, similar to a pap smear, and does not require anesthesia. Thawed embryos are placed into a catheter and then introduced into the uterus through the cervix, a process typically painless and quick.

Benefits of FET

• FETs allow for pregnancy attempts with previously frozen embryos, offering a less invasive option compared to a full IVF cycle.
• They provide medical and logistical benefits, including better preparation of the uterine lining and easier scheduling.
• The process from preparation to transfer is carefully managed to optimize conditions for embryo implantation and increase the chances of a successful pregnancy.