Frozen Embryo Transfer

Frozen Embryo Transfer (FET) is an in vitro fertilization (IVF) procedure in which an embryo that was previously created and frozen during an earlier IVF cycle is thawed and transferred into a woman’s uterus. FET offers a flexible and less invasive option for couples or individuals who have undergone a prior egg retrieval and fertilization cycle, with embryos stored for future use.

Why is FET Preferred?

Frozen Embryo Transfer is often chosen in several specific situations:

• Risk of Ovarian Hyperstimulation Syndrome (OHSS):

  • OHSS can occur in women who have undergone ovarian stimulation for IVF. It results from an excessive response to fertility medications, leading to swollen, painful ovaries and fluid accumulation in the abdomen. In cases where a doctor suspects a high risk of OHSS, FET is preferred because it allows the ovaries to recover after stimulation. The embryos are frozen for later use, reducing the immediate risk of OHSS.

• Preimplantation Genetic Testing (PGT):

  • PGT is a screening process that checks embryos for genetic abnormalities before they are transferred to the uterus. This testing can be essential for couples with a history of genetic disorders, recurrent pregnancy loss, or advanced maternal age. By freezing the embryos while awaiting PGT results, FET ensures that only genetically healthy embryos are transferred at a later date, improving the chances of a successful pregnancy.

• Pre-treatment Before Embryo Transfer:

  • In some cases, a woman may require additional treatments or preparation before the embryo transfer. This may include hormonal treatments to optimize the uterine lining or time to recover from a medical condition. FET allows flexibility, as the embryos are cryopreserved until the woman’s body is ready for transfer.

The Frozen Embryo Transfer Process

• Thawing the Embryo:

  • The cryopreserved embryo is carefully thawed in a laboratory using controlled processes to ensure its viability. Modern freezing techniques, such as vitrification, result in high survival rates for thawed embryos.

• Preparing the Uterus:

  • To ensure the uterus is in the best condition for embryo implantation, a woman may be given hormonal treatments like estrogen and progesterone to prepare the uterine lining. The doctor closely monitors the woman’s hormonal levels and the thickness of the endometrial lining through ultrasound.

• Embryo Transfer:

  • Once the uterus is ready, the thawed embryo is transferred into the uterus using a thin catheter. This is a simple, minimally invasive procedure and does not typically require sedation.

• Post-Transfer Monitoring:

  • After the transfer, the woman will be monitored, and hormone support may continue to help ensure successful implantation. A pregnancy test is usually performed about 10 to 14 days after the transfer to determine if the procedure was successful.