How is cryofreezing of embryos and their defrosting carried out. Cryopreservation and storage of frozen embryos

1. 🩺 Embryo cryopreservation: how, when and why
2. 🤰 Cryofreezing of embryos for IVF: use in reproductive programs
3. ⭐ Surrogate mother and cryoprotocol: dark sides

Embryo cryopreservation: how, when and why

In a simplified form, the procedure looks like this:

1. A woman undergoes a puncture of the follicles from which the eggs are removed (about 10 after hormone therapy and 1 (rarely 2) if the program is carried out in a natural cycle).
2. The embryologist examines the received oocytes, selects the highest quality and most promising in terms of fertilization.
3. An IVF/ICSI/PICSI protocol is carried out: the eggs are combined with selected high-quality spermatozoa. Embryosareformed.
4. The embryologist examines the embryos and selects the most viable and promising. He puts them in test tubes, adds a cryoprotectant (a substance based on glycerin that replaces water in the interstitial fluid).
5. Embryos in test tubes are placed in a Dewar vessel filled with liquid nitrogen. Under the influence of nitrogen, the cryoprotectant passes into a solid state, preserving the viability of the embryos.
6. The storage of frozen embryos in a cryobank can last for decades, but the period recommended by reproductologists is 10-15 years.
7. Obtaining a personal certificate confirming the storage of oocytes.

According to the same scenario, excluding the IVF procedure, eggs and sperm can be frozen and stored.

The described procedure creates a win-win situation for all parties.

For embryologists, this is an opportunity to carry out international reproductive programs (for example, when future parents conduct a program in a country where surrogacy is allowed). It is also an opportunity to form a cryobank that allows couples to become parents two and three times without hormone therapy. This is the donation of oocytes / adoption of embryos for those who dream of becoming parents, but nature is against their desire.

For women, this is an opportunity to plan expanding the family for a suitable period, as well as “reproductive back up” in case of the threat of early menopause, before chemotherapy or surgical interventions that can disrupt reproductive function.

From the point of view of the quality of the biomaterial, it is recommended to resort to the procedure until the age of 35, since with age, mutations accumulate in oocytes that reduce the likelihood of creating a healthy embryo and the subsequent birth of a healthy child. In good reproductive clinics, embryos after thawing are cultured, a biopsy and PGD are carried out. Thanks to all these manipulations, the chances of pregnancy, depending on the age and quality of the embryos, vary from 30 to 80%.

It is important to mention that under the same equal conditions, the pregnancy rate after the transfer of thawed embryos is 50-70%, which is 2-3 times higher than with the transfer of fresh ones.

Cryofreezing of embryos for IVF: use in reproductive programs

Good reproductive clinics value the reputation that only high success rates in reproductive programs can provide. This is the reason for the requirements and conditions for working with the base of cryo-frozen embryos of clients. Strict adherence to them increases the likelihood of pregnancy and the subsequent birth of a healthy child. This is a common goal for both future parents and the clinic.

When the clinic works for the result, only embryos that really have a high implantation potential are subject to freezing. That is, the ones that have undergone cultivation, biopsy, pre-implantation genetic diagnosis. If a clinic provides only the embryo freezing service, most likely there will be poor-quality ones among them.

Surrogate mother and cryoprotocol: dark sides

If the program involves a surrogate mother who will have to carry a cryo-frozen embryo brought from abroad, there is an increased risk for her and future parents and many issues:

Surrogate mothers are very worried about the quality of the brought embryos, since the implantation of underexamined embryos of unknown quality can lead to spontaneous abortion or the need for termination due to pathologies detected by amniocentesis or chorionic villus biopsy. This is a traumatic scenario in every sense: failed parents pay with dashed hopes, a surrogate mother with her health. There are very few who want to carry a pregnancy with such risks, so the fee for a surrogate mother in such situations is significantly higher than when working according to the rules of the clinic.

Even with very good clinics there were dark stories. Freezing of a low-quality embryo (accidental or intentional, if customers are simply sold a vitrification service), mixed up genetic material (fraught with criminal liability). All responsibility for such cases will fall on the clinic in which the transfer will be performed, as well as on the surrogate mother. This will increase the cost of the program: you need to find a surrogate mother who agrees to a risky program, as well as lawyers in case of legal claims from clients.

Given the above, you should avoid suspiciously cheap (less than $ 50,000) programs with your own embryos. This is not only dangerous for the health of the future child, but also involves a long waiting list for the program, possible costs for the expectant mother (caesarean section without sufficient reason). A low price absolutely always means increased risks for customers, as well as their future children. The price of "economizing" in this case is too high.

Legal aspects and rules for working with the base of cryo-frozen embryos

If you are interested in a safe reproductive program from the medical and legal side, then Feskov Human Reproduction Group has many years of experience in just such work. For the safety of all participants, the following rules and restrictions apply:

• Undocumented embryos brought from dubious clinics and countries are not accepted.
• Embryo transport is carried out by certified couriers of our clinic, using our equipment with a mandatory tracker and constant monitoring of the conditions necessary for the survival of the embryos.

It should be understood that the survival of embryos after thawing is not 100%,
Therefore, the control of transportation conditions is an extremely important measure for
keeping as many viable ones as possible.

• Mandatory research to confirm the genetic relationship with the mother and father of this embryo.

Attention! In the absence of relationship (an error in the creation, storage or transportation of the embryo), criminal liability arises for all participants in the program (clients, surrogate mother and clinic).

• Parents must be officially married or a waiver of parental rights of one of the partners must be issued.

Our clinic performs mandatory cultivation, biopsy and PGD of imported embryos to be sure of their quality.

Despite the apparent abundance of procedures, we will be able to start the IVF program as early as 7 days after the arrival of the embryos in our clinic!

Compliance with the above rules allows us to guarantee your complete legal security and the highest possible chances for successful IVF and guarantee the birth of a healthy child.

In Feskov Human Reproduction Group, all programs provide for the possibility of switching to work with your own embryos / eggs on the principles of guaranteed unlimited programs. We offer our clients our own cryobank with donor eggs/donor sperm. In this case, one of the parents will have a genetic connection with the child. An embryo adoption service is also available if both partners have problems with the reproductive material.

Future clients should know that our clinic has a truly individual approach: we understand that package programs may not include all the services you desire. Therefore, any package can be supplemented with the necessary options at your request. Just tell the manager about your desires, Feskov Human Reproduction Group will fulfill them.

Authors, contributors:

Olena Somova
Embryologist

published: 20 May 2022
updated   : 03 March 2023

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