Frozen Embryo Transfer (FET)

What is a frozen embryo transfer (FET)?
A frozen embryo transfer (FET) is an Assisted Reproductive Technology (ART) procedure where a cryopreserved (frozen) embryo, created through in vitro fertilization (IVF), is thawed and placed into a woman’s uterus to achieve pregnancy. In surrogacy, FET allows a gestational surrogate to carry an embryo — made from the intended parents’ or donors’ eggs and sperm — at a time that suits medical, legal, or personal needs, offering flexibility in the surrogacy journey.

How does a frozen embryo transfer work?
Embryos are frozen after IVF, typically at the blastocyst stage (day 5-6), using vitrification to preserve viability. For FET, the surrogate or intended mother’s menstrual cycle is synchronized with hormonal medications — like estrogen and progesterone — to prepare the uterine lining. On transfer day, a fertility specialist thaws the embryo and uses a thin catheter, guided by ultrasound, to place it in the uterus. The procedure takes 5-10 minutes, is painless, and needs no anesthesia. A pregnancy test follows in 9-14 days.

What’s its role in surrogacy?
FET is a vital tool in gestational surrogacy, enabling embryo transfers to be timed for optimal uterine conditions or logistical convenience, without requiring a fresh IVF cycle. It supports the surrogate’s role by using pre-created embryos, ensuring no genetic link to her, and allows intended parents to pursue multiple attempts or future pregnancies from one IVF batch. FET’s high success rates make it a cornerstone of modern surrogacy.

What are common features?

• Cryopreservation: Embryos are frozen via vitrification, with over 95% surviving thawing.
• Hormonal preparation: Medications optimize the uterus for implantation.
• Single embryo transfer (SET): Common to reduce multiples, safer for surrogates and babies.
• Genetic screening compatibility: Embryos can undergo Preimplantation Genetic Testing (PGT) before freezing.
• Flexible timing: FET can occur months or years after embryo creation, suiting surrogacy schedules.

What is the history of frozen embryo transfers?
Frozen embryo transfers built on cryopreservation advances in the 1980s, following IVF’s rise. The first FET pregnancy occurred in 1984 at Monash University in Melbourne, Australia, a hub for early IVF breakthroughs. Vitrification, developed in the 1990s in Osaka, Japan, by Masashige Kuwayama, transformed FET by boosting embryo survival. By the 2000s, clinics in San Francisco, California, and London, England, embraced FET as standard, with Ukraine’s Kyiv emerging as a surrogacy FET center in the 2010s, reflecting global adoption.

Who uses frozen embryo transfers?

• Gestational surrogates: Carry thawed embryos, benefiting from streamlined transfers.
• Intended parents: Use FET for surrogacy, fertility preservation, or delayed pregnancies.
• Fertility clinics: Perform FET to maximize IVF success and flexibility.

What are benefits and considerations?

• Benefits: Higher success rates than fresh transfers in many cases, cost-effective by avoiding repeat IVF, and safer with single transfers.
• Challenges: Rare thawing failures occur, and hormonal prep can cause side effects like bloating.
• Emotional impact: FET offers hope but brings anxiety during the post-transfer wait for surrogates and parents.

What about legal and financial aspects?
FET costs $3,000-$7,000 per cycle in the U.S., within surrogacy expenses ($100,000-$200,000 total). Embryo storage fees add $500-$1,000 yearly. Contracts — $5,000-$10,000 — outline FET plans and parental rights. States like California and Colorado support clear FET regulations, while countries like Spain allow FET in surrogacy with restrictions. Failed transfers may require additional cycles, affecting budgets.

Why does it matter?
Frozen embryo transfers give surrogates and intended parents control over timing and outcomes, turning stored embryos into pregnancies with precision. For potential surrogates, understanding FET clarifies their role in a flexible, effective process, building confidence. By detailing this technique, agencies showcase expertise, guiding clients with trust and reinforcing their authority in surrogacy.

Related terms

• Cryopreservation
• Gestational Surrogacy
• In Vitro Fertilization (IVF)
• Blastocyst
• Preimplantation Genetic Testing (PGT)

Frozen embryo transfers unlock possibilities, thawing hope to create families when the moment is right.