Embryo Freezing: Benefits & Success Rate

What is Embryo Freezing?

Embryo freezing is a crucial component of assisted reproductive technology (ART). It involves the preservation of fertilized eggs (embryos) by cooling them to extremely low temperatures, typically around -196 degrees Celsius (-321 degrees Fahrenheit), using a process known as vitrification. This freezing method prevents the formation of ice crystals within the embryos, ensuring their structural integrity and viability for an extended period.

The embryos are typically frozen at a very early developmental stage, usually after just a few days of growth. Once frozen, these embryos can remain in storage for an indefinite period, theoretically preserving fertility potential for many years.

Why Should You Freeze Embryo?

Embryo freezing offers several compelling reasons for its use:

1. Fertility Preservation: Embryo freezing is often employed in cases where individuals or couples are facing fertility-threatening circumstances, such as cancer treatment or surgery that may harm reproductive organs. Freezing embryos before undergoing these procedures can provide a chance to have biological children in the future.
2. Age-Related Fertility Preservation: As a woman’s age advances, the quality and quantity of her eggs decrease, which can impact her ability to conceive naturally. By freezing embryos when eggs are younger and healthier, women can potentially increase their chances of successful pregnancy when they are ready to have children.
3. Genetic Testing: Embryo freezing is commonly used in conjunction with preimplantation genetic testing (PGT). This allows for the screening of embryos for genetic disorders before implantation, reducing the risk of passing on inheritable diseases to offspring.
4. Assisted Reproduction: Couples undergoing in vitro fertilization (IVF) often produce more embryos than can be transferred during a single cycle. By freezing surplus embryos, they can be used in subsequent IVF cycles, saving both time and money.

What is the Process of Embryo Freezing?

The process of embryo freezing involves several distinct steps:

1. Ovarian Stimulation and Egg Retrieval: In an IVF cycle, a woman typically undergoes ovarian stimulation with hormones to produce multiple eggs. Once the eggs are mature, they are retrieved via a minimally invasive procedure known as transvaginal ultrasound-guided aspiration.
2. Fertilization: The retrieved eggs are then fertilized with sperm in a laboratory setting. This can be achieved through conventional insemination or intracytoplasmic sperm injection (ICSI), where a single sperm is injected directly into an egg.
3. Embryo Culture: The fertilized eggs are cultured for a few days, typically five or six, to allow them to develop into embryos. During this time, they are closely monitored for signs of healthy growth.
4. Vitrification: The embryos that meet the desired developmental criteria are selected for vitrification. In this process, the embryos are rapidly cooled and plunged into liquid nitrogen, which prevents the formation of ice crystals and preserves their structural integrity.
5. Storage: Once vitrified, the embryos are placed in specialized cryogenic storage containers and stored in liquid nitrogen tanks, where they can remain indefinitely until the intended parents decide to use them.
6. Thawing and Transfer: When the individuals or couples are ready to use the frozen embryos, the selected embryos are thawed and transferred into the woman’s uterus during an embryo transfer procedure, often referred to as a frozen embryo transfer (FET).

What’s the Difference Between Egg Freezing vs. Embryo Freezing

While both egg freezing and embryo freezing are fertility preservation techniques, they differ significantly in several key aspects:

1. Timing: Egg freezing involves preserving unfertilized eggs, typically before any sperm-egg interaction. Embryo freezing, on the other hand, requires fertilization to create embryos before freezing.
2. Biological Parenthood: Egg freezing preserves the genetic material of one individual (the egg provider), while embryo freezing preserves genetic material from both partners (egg provider and sperm provider).
3. Genetic Testing: Genetic testing (PGT) can be performed on embryos before freezing, allowing for the selection of healthy embryos. This is not possible with egg freezing, as genetic testing can only be performed after fertilization.
4. Success Rates: Embryo freezing generally has higher success rates in terms of pregnancy and live birth compared to egg freezing. This is partly due to the fact that embryos have already passed a critical stage of development before freezing.
5. Embryo Ownership: The legal and ethical considerations surrounding the ownership and disposition of embryos can be complex and may vary by jurisdiction. This is less of an issue with egg freezing, as the genetic material belongs solely to the individual.

Advantages of Embryo Cryopreservation

Embryo cryopreservation presents several compelling advantages:

1. Increased Pregnancy Success Rates: One of the primary advantages of embryo cryopreservation is its ability to improve pregnancy success rates. Frozen embryos have a higher chance of survival and implantation compared to fresh embryos, as they are not affected by the hormonal fluctuations associated with fresh embryo transfer.
2. Flexibility in Timing: Frozen embryos can be stored for an extended period, providing flexibility in family planning. This allows individuals or couples to undergo additional fertility treatments or delay pregnancy until they are emotionally or financially ready.
3. Preimplantation Genetic Testing (PGT): Embryo cryopreservation allows for the selection and testing of embryos for genetic abnormalities before transfer. This reduces the risk of passing on genetic disorders to offspring.
4. Reduced Medication Costs: FET cycles generally require fewer medications for ovarian stimulation and synchronization, making them more cost-effective than fresh IVF cycles.
5. Preservation of Fertility: Individuals facing medical treatments, such as chemotherapy or radiation, that may compromise their fertility can preserve their embryos for future use. This offers hope for biological parenthood after recovery.

What Are the Risks of Embryo Freezing?

While embryo cryopreservation offers numerous benefits, it also carries some risks:

1. Survival Rate: Not all embryos survive the freezing and thawing process. The success of cryopreservation depends on the quality of the embryos, the expertise of the laboratory, and the effectiveness of the cryopreservation technique.
2. Multiple Pregnancies: In some cases, multiple embryos are transferred during FET to improve the chances of pregnancy. This can lead to higher-order multiple pregnancies (triplets or more), which carry increased health risks for both the mother and babies.
3. Emotional Stress: The emotional stress associated with waiting for a frozen embryo transfer and uncertainty about the outcome can be challenging for individuals and couples.
4. Storage Costs: Ongoing storage of frozen embryos incurs annual fees, which can be a financial burden for some individuals or couples.

IVF Success Rate with Frozen Embryo Transfer in India

The success rate of IVF with frozen embryo transfer in India can vary based on multiple factors, including the clinic’s expertise, the patient’s age, the quality of the embryos, and underlying fertility issues. However, India has seen a significant increase in the use of frozen embryo transfer in recent years, and the success rates have generally been promising.

As of my last knowledge update in September 2021, the success rates for FET in India were comparable to or slightly higher than those for fresh embryo transfers. The success rates for FET often ranged from 40% to 60%, but these figures can change over time as technology and techniques improve.

It’s important to note that success rates can vary from one fertility clinic to another. Patients should consult with their healthcare providers to get the most accurate and up-to-date information on success rates specific to their situation.

Cost of Embryo Freezing in India

The cost of embryo freezing in India generally ranges from INR 20,000 to INR 50,000 (approximately $270 to $680 USD) per cycle. The embryo freezing cost in India can also vary widely depending on several factors, including the clinic’s location, reputation, and the specific services offered.

Additional costs to consider include storage fees for the frozen embryos, which can range from INR 5,000 to INR 10,000 (approximately $68 to $136 USD) per year. It’s essential for individuals or couples to inquire about the complete pricing structure at their chosen fertility clinic, including any hidden fees or additional services.

Furthermore, some fertility clinics may offer package deals that include multiple IVF cycles, embryo freezing, and frozen embryo transfers at a bundled price. These packages can provide cost savings compared to paying for each service separately.

How Long Can an Embryo Be Frozen?

Embryos can be safely frozen for an extended period, theoretically indefinitely, without significant loss of quality or viability. The exact duration embryos can remain frozen depends on various factors, including the cryopreservation technique used, the quality of the embryos, and the storage conditions. The most common method for embryo freezing is vitrification, which minimizes ice crystal formation and ensures the embryos’ structural integrity.

Many fertility clinics routinely store frozen embryos for five, ten, or even more years with successful outcomes. However, it’s important to note that each country or region may have regulations governing the maximum storage duration for frozen embryos, and these regulations can vary. Before reaching the maximum storage duration, individuals or couples may need to decide whether to use, discard, donate, or continue storing their frozen embryos.

At What Age Can You Freeze an Embryo?

Embryo freezing typically involves individuals or couples undergoing in vitro fertilization (IVF) treatment. Therefore, the age at which embryo freezing becomes an option depends on a person’s or couple’s readiness and specific circumstances rather than a set age limit.

However, it’s important to consider that the success of embryo freezing is often linked to the quality of the eggs used to create the embryos. As a woman’s age advances, the quality and quantity of her eggs decline, which can impact the success rates of both IVF and frozen embryo transfer (FET). Generally, individuals and couples choose to freeze embryos when they are in their reproductive prime, typically in their 20s to early 30s, to maximize the chances of successful pregnancy when they are ready to have children. That said, some individuals may choose to freeze embryos at older ages, understanding that the chances of success may decrease.

Is Embryo Freezing Painful?

Embryo freezing itself is not a painful procedure. It occurs in a controlled laboratory setting, and the embryos are frozen without causing any discomfort to the individuals involved. The embryo freezing process primarily involves the following steps:

1. Ovarian Stimulation: This may involve daily hormone injections, which can cause mild discomfort but are generally well-tolerated.
2. Egg Retrieval: This minimally invasive procedure is typically performed under sedation or anesthesia, ensuring that individuals do not experience pain during the process.
3. Embryo Culture and Vitrification: Individuals do not undergo any procedures or experience pain during these stages, as they occur in the laboratory.
4. Thawing and Transfer: When individuals or couples decide to use frozen embryos, the thawing and transfer process involves minimal discomfort, similar to a routine gynecological procedure.

While the embryo freezing process itself is not painful, some individuals may experience emotional stress or discomfort related to the hormone injections or the overall fertility treatment journey. It’s important for healthcare providers to provide appropriate support and guidance to manage any emotional or physical discomfort associated with the process.

Is Freezing Embryos Safe?

Embryo freezing is considered a safe and established technique in assisted reproductive technology (ART). The safety of the process largely depends on the quality and experience of the fertility clinic and laboratory performing the procedures.

Some potential risks and considerations associated with embryo freezing include:

• Embryo Survival: While modern vitrification techniques have significantly improved embryo survival rates, not all embryos may survive the freezing and thawing process.
• Multiple Pregnancies: Transferring multiple frozen embryos to increase the chances of pregnancy can lead to higher-order multiple pregnancies (e.g., triplets or more), which carry increased health risks.
• Ethical and Legal Issues: The ownership, disposition, and use of frozen embryos can raise ethical and legal concerns. Individuals and couples should discuss and document their wishes regarding these aspects.

Overall, when performed by experienced and accredited fertility clinics, embryo freezing is considered a safe and effective option for preserving fertility and achieving pregnancy.

Are 2 Frozen Embryos Good?

The quality and viability of frozen embryos can vary depending on multiple factors, including the quality of the original eggs, the skill of the laboratory staff, and the cryopreservation technique used. However, having two frozen embryos can be a positive sign in many cases.

Having multiple frozen embryos provides individuals or couples with the option to undergo multiple frozen embryo transfer (FET) cycles if needed. This can increase the chances of achieving a successful pregnancy without the need for additional IVF cycles. However, the decision to transfer one or two embryos during a FET cycle depends on several factors:

• Age: Younger individuals may opt to transfer a single embryo to reduce the risk of multiple pregnancies.
• Embryo Quality: The quality of the embryos plays a significant role. If both embryos are of high quality, transferring two may be a suitable option.
• Medical History: Individual medical histories and specific fertility issues can influence the decision. A healthcare provider will assess the patient’s unique situation to make the best recommendation.
• Personal Preferences: The patient’s or couple’s personal preferences and willingness to accept the potential for a multiple pregnancy are important considerations.

Ultimately, the decision about the number of embryos to transfer during a FET cycle should be made in consultation with a fertility specialist who can provide personalized guidance based on the individual’s or couple’s circumstances and goals.