Frozen Embryo Transfer: Who is it for and When to Try it?

What is a Frozen Embryo Transfer (FET)? 

Frozen Embryo Transfer is a cycle where a vitrified embryo left from a previous fresh IVF cycle is devitrified and transferred back into a mother’s or in the case of using a vitrified embryo for Surrogacy — the Gestational Carrier’s uterus.

Who is it for? 

• Singles and couples desiring to use the embryos generated in the previous IVF cycle(s) instead of starting a new IVF cycle.
• Singles and couples wishing to use the vitrified embryos left after the previous IVF/Surrogacy cycle in Surrogacy. 

When to try it? 

• If you want to eliminate starting a new IVF cycle from the beginning.
• If you want to have a backup option in the ongoing fresh IVF cycle. 
• If you are working with a Surrogacy Agency and would like to use a frozen embryo in Surrogacy. 

What types of FET are there?

There are two kinds of FET cycles: hormonal support cycles involving administration of the fertility drugs to prepare the maternal endometrium for implantation and natural cycles without using medication except the hCG shot typically given to trigger ovulation.

What are my options? 

• FET using a cleavage stage embryo or a blastocyst. 
• FET with an elective single Embryo Transfer (eSET) or elective single blastocyst transfer. 
• FET with a transfer of two cleavage stage embryos or two blastocysts. 
• FET using a male or female embryo (if PGT has been done before vitrification).
• FET with Gender Selection (PGD) before transfer. 
• FET with Preimplantation Genetic Testing before transfer.
• Multicycle FET with one or more transfer cycles as a backup option in case of a negative result. 

How long does the FET cycle take?

On average, a single FET cycle takes about 6 to 8 weeks. However, the FET cycle timeline can take longer in some cases, depending on the Treatment Protocol, endometrial receptivity of the mother, using the embryo stored in the clinic or shipping an embryo from abroad (shipping can take 1–2 months), and the other cycle–related conditions. 

Frozen Embryo Transfer Success Rates

According to the latest statistical results the pregnancy rates after a single vitrified–devitrified blastocyst transfer range from 50 to 79% depending on the freezing technique (slow–freezing has lower survival rates compared to Vitrification which has up to 100% of survival rates), quality of the embryo, endometrial receptivity of the mother, and other cycle–specific conditions.