Freezing Embryos Vs Freezing Eggs

Diagnosis & Treatment July 19, 2024 August 6, 2024

Fertility preservation is a personal journey, with reasons varying from person to person. Some patients may want to keep the option of starting a family later in life, while others may wish to delay having children for a few more years.

If you have a partner, you might wonder about freezing embryos vs freezing eggs. While both options offer the potential to extend your biological clock, each has unique advantages and considerations. So, in this article, we examine at the differences between these options.

Is It Better To Freeze Eggs Or Embryos?

The answer to this question ultimately comes down to your personal preferences. They may have similar success rates; however, freezing solely one’s eggs can offer more options for the future.

For example, if a certain partnership doesn’t work out, frozen eggs can still be used, whereas frozen embryos are not useable without the other party’s consent. Below, we explore these options further, including their pros and cons.

How Are Eggs Frozen?

The process of freezing eggs, also known as oocyte cryopreservation, involves several steps, including:

Ovarian stimulation: Medications, typically injectable hormones, are used to stimulate the ovaries to produce multiple eggs.
Monitoring: During the stimulation phase, regular ultrasounds and blood tests are performed to monitor the development of the follicles containing the eggs. These first two steps usually take about 7-14 days.
Trigger Shot: Once the follicles reach a certain size, a trigger shot is administered, stimulating the final maturation of the eggs and priming the body for the egg retrieval process.
Egg retrieval: During the egg retrieval, the eggs are collected from the ovaries under sedation; this procedure is performed vaginally using a needle guided by an ultrasound probe.
Egg preparation: The retrieved eggs are then prepared for freezing. A special AI report (called Violet) will be generated and discussed with you by your physician. This image-based tool will provide some important insight into the quality of your eggs, based strictly on the appearance of the mature eggs that were frozen.
Vitrification: The mature eggs are then flash-frozen using a rapid freezing method called vitrification. This process involves dehydrating the eggs and replacing the water with a cryoprotectant solution to prevent ice crystal formation.
Storage: The frozen eggs are stored in liquid nitrogen tanks at -196°C (-320°F) until they are ready to be used.

When the individual is ready to use the frozen eggs, they are thawed and fertilized with sperm through a process called intracytoplasmic sperm injection (ICSI), and the resulting embryos are transferred to the uterus.

Pros And Cons Of Freezing Eggs

So, what should you consider when deciding on freezing eggs vs freezing embryos?

Here are the pros of egg freezing:

Fertility preservation: Egg freezing allows individuals to preserve their fertility potential, especially if they are not ready to start a family or have medical conditions that may impact their future fertility.
Increased flexibility: Freezing eggs gives individuals more control over their reproductive timeline, allowing them to pursue personal, educational, or career goals without the pressure of a ticking biological clock.
Reduced risk of chromosomal abnormalities: With increasing age, the risk of chromosomal abnormalities in an individual’s eggs increases. Thus, freezing eggs at a younger age can help reduce this risk when the eggs are used in the future.
Improved success rates: Advances in egg-freezing technology, particularly vitrification, have led to better egg survival rates and improved pregnancy outcomes compared to older slow-freezing methods.
No need for a sperm donor or partner: Freezing eggs allows individuals to preserve their fertility, without a sperm donor or partner at the time of freezing.

On the flip side, here are the potential cons of egg freezing:

Cost: Egg freezing can be expensive when you include medications, procedures, and ongoing storage fees. Insurance coverage for elective egg freezing is often limited (depending on your benefits package).
No guaranteed success: While egg freezing can increase the chances of having a biological child in the future, there is no guarantee of success. The success rates depend on factors such as age at the time of freezing, egg quality, and the number of eggs frozen.
Limited information: We can gain some insight into the health status of eggs based on their appearance, but there is no equivalent rating for sperm. As a result, there is no guarantee that the eggs will develop into high-quality embryos. Your fertility team will obtain more information after the eggs are fertilized with sperm.
Medical risks: The egg freezing process involves ovarian stimulation and egg retrieval, which carry some medical risks, such as ovarian hyperstimulation syndrome (OHSS) or surgical complications — although these risks are low.
Emotional impact: The decision to freeze eggs can be emotionally complex, and some individuals may feel pressure or anxiety about their fertility or the success of future fertility treatments.
Limited time for using frozen eggs: While eggs can be stored indefinitely, the optimal time to use them is before the individual reaches advanced maternal age, typically before age 45, to ensure the best possible pregnancy outcomes.

How Are Embryos Frozen?

The steps for freezing embryos are similar to those for freezing eggs. The process begins with ovarian stimulation, monitoring, and egg retrieval, as described in the egg freezing section above.

However, after the eggs are retrieved, other steps are involved in creating and freezing embryos. These steps include:

Fertilization: After egg retrieval, the mature eggs are fertilized with sperm in the laboratory using either conventional IVF or intracytoplasmic sperm injection (ICSI). In conventional IVF, the eggs and sperm are mixed in a dish, allowing for natural fertilization. In ICSI, a single sperm is directly injected into each mature egg.
Embryo development: The fertilized eggs, now called zygotes, are cultured in the laboratory for several days, allowing them to develop into embryos. Embryos are typically frozen at the blastocyst stage (day 5 or 6, when the embryo has about 100-200 cells).
Embryo grading: Before freezing, embryos are graded based on their appearance and developmental potential. High-quality embryos have a better chance of surviving the freezing and thawing process and leading to a successful pregnancy.
Vitrification: Similar to egg freezing, the embryos are then flash-frozen using the vitrification method. The embryos are dehydrated and treated with cryoprotectants to prevent ice crystal formation during the rapid freezing process. They are then stored in liquid nitrogen until they are ready to be used.

Pros And Cons Of Freezing Embryos

Similar to egg freezing, there are many advantages of freezing embryos and the final decision may depend on your specific situation.

Some pros of freezing embryos include:

Slightly higher success rates: Frozen embryo transfer (FET) cycles have been shown to have similar or even higher success rates compared to fresh embryo transfer cycles. However, it’s worth noting that success rates between embryo freezing and egg freezing are very similar and that the outcomes largely depend on the age at which the eggs were frozen or embryos were created.
Genetic testing: Embryos can be tested for genetic disorders before freezing, allowing for the selection and transfer of chromosomally normal embryos. In turn, this may increase the chances of a successful pregnancy and reduce the risk of miscarriage.

In contrast, cons of embryo freezing may involve:

Ethical considerations: Some individuals may have moral or religious objections to creating and storing embryos. There may also be concerns about the disposition of unused embryos.
Cost: Embryo freezing involves additional expenses, such as the creation of the embryo and genetic testing, when compared to egg freezing.
Sperm source required: Unlike egg freezing, embryo freezing requires a sperm source at the time of fertilization, which may not be available or desirable for some individuals.
Potential for decreased embryo quality: Although vitrification has greatly improved the survival rates of frozen embryos, there is still a small risk of embryo damage during the freezing and thawing process.
Legal considerations: If a couple freezes embryos together, there may be legal issues to consider if the couple separates or divorces, as both parties have a say in the disposition of the embryos.

Success Rate Of Freezing Eggs Vs Embryos

The success rate of freezing eggs vs embryos is very similar, with frozen embryos potentially having a slightly higher survival rate when undergoing the thawing process. Generally, embryos are considered more stable and less fragile than eggs since they have more cells and structure, which may improve these outcomes.

However, again, it’s important to consider other factors, such as the age of egg freezing, current health status, and more.

Freezing Eggs Vs Embryos Cost

An egg freezing cycle typically ranges from $8,000 to $10,000, plus the cost of fertility medications. Ultimately, freezing embryos requires more upfront costs because of the inclusion of sperm preparation and fertilization (IVF or ICSI) and embryo culture and grading processes, which may add $6,000 to $8,000. Embryo freezing may also involve additional costs, such as Preimplantation Genetic Testing (PGT), which can be between $2,000 and $6,000. Note that these are ranges, and for pricing that is specific to your circumstances, please consult with the clinic.

This means that the decision to freeze eggs or embryos may come down to your budget or insurance coverage. At EVOLVE, we encourage all our patients to review their insurance plans and determine whether they are applicable before committing. EVOLVE is also thrilled to offer financing options and an in-house financial coordinator who can help you determine the best next step. For more information, contact our caring and compassionate team today!

References:
https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/freezing-embryos