How to Freeze Embryos

Embryo freezing via in vitro fertilization (IVF) is a standard phase of gestational surrogacy that gives your fertility clinic complete control over transfer timing.

Creating and preserving embryos before matching allows you to focus on selecting the right gestational carrier without placing unnecessary pressure on your medical schedule.

Knowing how embryo freezing works helps you plan your family-building timeline, set financial expectations, and coordinate smoothly with your clinical team.

When you are ready to evaluate your options for building a family, you can connect with a specialist to discuss the next steps in your surrogacy journey.

How the Embryo Freezing Process Works

Creating frozen embryos for a surrogacy journey begins at your fertility clinic with egg retrieval and sperm collection. Your reproductive endocrinologist uses medications to stimulate the ovaries, retrieves mature eggs, and fertilizes them in the laboratory using standard insemination or intracytoplasmic sperm injection (ICSI).

Over the next five to six days, fertilized eggs culture in the laboratory until they reach the blastocyst stage. Embryologists evaluate these blastocysts using standard grading criteria that assess cellular structure and developmental potential. Understanding how embryo grading works helps you interpret lab reports alongside your clinical team.

Many intended parents opt for preimplantation genetic testing for aneuploidy (PGT-A) to confirm chromosomal health. This screening involves removing a small biopsy from the outer layer of the blastocyst before freezing.

Once graded or tested, the embryology team uses vitrification to freeze the specimens. This ultra-rapid cooling technique transforms liquid within the cells into a glass-like solid state, preventing damaging ice crystals from forming.

• Egg retrieval and insemination collect eggs and sperm to generate fertilized embryos in the lab.
• Blastocyst culture allows embryos to mature for 5–6 days until reaching advanced cellular development.
• Optional PGT-A screening verifies chromosomal health prior to long-term laboratory storage.
• Vitrification preserves blastocysts almost instantly at peak viability for future transfer cycles.

Where Frozen Embryos Are Stored Until Transfer

Following vitrification, embryos rest in liquid nitrogen storage tanks cooled to -196°C. These ultra-low temperatures temporarily stop all biological activity, keeping embryos safely preserved for years without loss of quality.

Initial storage takes place directly inside your fertility clinic’s laboratory. If you need long-term preservation while preparing for surrogacy, your clinic may transport them to a secure third-party cryobank equipped with continuous temperature monitoring and backup power systems.

• Ongoing storage fees apply for annual preservation paid to the clinic or cryobank facility.
• Strict chain-of-custody tracking protects specimen identity, security, and laboratory records.
• Legal consent forms detail ownership rights and outline disposition directives for unexpected circumstances.

Using Previously Frozen Embryos for Surrogacy

Intended parents who created and stored embryos during past IVF treatments can use those existing specimens for gestational surrogacy. Before moving forward, the receiving fertility clinic performs a complete medical record review to confirm viability.

Your physician will evaluate previous embryology reports, freeze protocols, and genetic screening data. Deciding whether to use existing embryos or create new embryos is a key medical and financial decision best made in consultation with your reproductive endocrinologist.

When your stored embryos reside at a different lab than your surrogate’s designated clinic, they require physical relocation. Licensed medical couriers transport liquid nitrogen dry shippers between facilities using monitored temperature tracking.

• Receiving clinic review evaluates historical grading, thawing protocols, and embryology reports.
• Legal authorization confirms clear legal ownership and executes parental consent documentation.
• Chain-of-custody transport utilizes temperature-logged shippers to protect viability during transit.
• Receiving lab clearance inspects and officially accepts incoming specimens into inventory.

Legal requirements also impact how you use preserved embryos across state lines.

Does Embryo Freezing Affect Success Rates?

Modern vitrification delivers post-thaw survival rates that routinely top 95% at established fertility practices. Frozen embryo transfers often achieve equal or higher pregnancy success rates than fresh transfers because the surrogate’s uterus can be prepared without the physical stress and altered hormone levels caused by egg retrieval medications.

Evaluating factors like IVF success factors helps establish realistic expectations for your transfer outcome.

• Blastocyst grade determines overall developmental quality at the exact time of vitrification.
• PGT-A testing confirms chromosomal normalcy to select the highest quality embryo for transfer.
• Provider age reflects the genetic age of the egg at the time of retrieval.
• Uterine receptivity measures the thickness and readiness of the surrogate’s lining on transfer day.

Freezing gives you logistical control without sacrificing transfer success. Having embryos safely stored lets you navigate surrogate matching, legal contracts, and medical clearances without rushing sensitive clinical timelines.

What Happens Before a Frozen Embryo Is Transferred to a Surrogate?

Transferring a preserved embryo to a gestational surrogate requires close coordination between your surrogacy agency, legal counsel, and medical team. Understanding the overall surrogacy process timeline clarifies how medical preparation fits alongside screening and legal agreements.

Before scheduling a transfer date, your surrogate completes psychological evaluations, background checks, and a comprehensive medical evaluation to secure final clinical clearance.

Once cleared, the surrogate begins a customized hormone regimen of estrogen and progesterone to prepare her uterine lining. The clinic monitors her response using bloodwork and transvaginal ultrasounds.

On transfer day, the embryology lab thaws a single blastocyst. The physician places the thawed embryo through the cervix and directly into the surrogate’s uterus using a thin catheter during a quick outpatient procedure.

Understand the Next Step in Your Surrogacy Journey

Completing IVF and preserving your embryos is a major milestone in your family-building plan. Having embryos stored gives you a firm foundation as you shift your focus to surrogate matching, legal agreements, and pregnancy.

Navigating clinical approvals, medical shipping, and agency requirements requires experienced oversight, but you do not have to manage these decisions alone.

When you are ready to move forward, you can connect with a specialist to discuss program options, evaluate financial protections, and take the next step toward meeting your surrogate.