Frozen Embryo Transfer (FET)

The frozen embryo transfer procedure (FET) is a highly effective method that allows the transfer of previously frozen embryos into the uterus. This technique eliminates the need for additional ovarian stimulation while maintaining high pregnancy success rates.

For many individuals and couples undergoing IVF, embryo cryopreservation provides an opportunity to attempt pregnancy at a later stage. Whether you are preparing for your first FET cycle or considering another attempt, understanding the frozen embryo transfer process step by step can help optimise your chances of success.

What is Frozen Embryo Transfer?

Understanding the Embryo Cryopreservation & Thawing Process

If you have undergone IVF before, you may have additional high-quality embryos that have been cryopreserved. Our clinic uses vitrification, a highly successful freezing technique, ensuring a 97% survival rate of embryos during the embryo thawing process. The success of a frozen embryo transfer cycle is comparable to fresh embryo transfers, provided the embryos survive thawing.

Embryo cryopreservation allows fertility preservation for individuals delaying parenthood or undergoing medical treatments that could impact fertility. The embryo thawing process is carefully managed to ensure the highest success rates.

1. Endometrial Preparation for FET

Before the transfer, your uterus is prepared using hormonal medications or a natural cycle approach. This step is crucial for embryo implantation. Endometrial preparation for FET may involve estrogen and progesterone therapy to create an optimal uterine lining.

3. Embryo Thawing Process

Thawed embryos are assessed for viability before transfer. The embryo thawing process is a delicate procedure, as embryos must survive the process to be transferred successfully.

5. Post-Transfer Phase

You may need progesterone supplementation in FET cycles, so follow a post-transfer protocol for optimal success. The frozen embryo transfer process timeline includes a waiting period before taking a pregnancy test.

5. The frozen embryo transfer process timeline varies based on whether you undergo a natural or medicated cycle. A medicated frozen embryo transfer timeline typically includes the following:
   • Week 1-2: Endometrial preparation with frozen embryo transfer drugs
   • Week 3: Embryo thawing and transfer
   • Week 4: Pregnancy test

   A natural cycle may follow a different FET timeline in the UK, depending on ovulation and hormonal levels.

• Natural FET Cycle: No medications, relies on the body’s natural cycle
• Medicated FET Cycle: Uses estrogen and progesterone for optimal endometrial preparation

The choice between natural vs. medicated frozen embryo transfer cycles depends on medical history and individual preferences.