Many couples dream of being happy parents, but such a diagnosis as infertility of one or both partners crosses out all hope. In this case, IVF comes to the rescue - a procedure that helps infertile couples give birth to a long-awaited child. It is necessary to carefully prepare for it, because a hormonal explosion in a woman's body leads to an increased production of eggs.

After that, a puncture of the ovaries is carried out, that is, a special needle is used to take the liquid from them with the eggs contained in it. They are separated and placed in specially created conditions, where they are fertilized and begin to divide. Then the embryos are transplanted into the uterine cavity, and the woman waits for the onset of pregnancy.

But it happens that in a test tube in which more embryos were formed than was necessary. In this case, doctors advise to carry out a procedure such as cryopreservation of embryos. They may be needed if the first IVF procedure was unsuccessful or the woman wants to have a second child in the future.

What is cryopreservation?

Cryopreservation of embryos is a procedure for their safe freezing with placement in a temperature of 196 degrees below zero. In this case, all biochemical processes stop, that is, the embryo stops developing, but if it is thawed, it remains viable.

Many women fail to get pregnant by IVF the first time. This happens only in 30-65% of cases. The second attempt forces the woman to undergo once again a very unpleasant and rather traumatic procedure for ovarian stimulation, as well as their puncture, accompanied by drug therapy.

Embryos frozen in liquid nitrogen can be considered a kind of safety net in case of failure. It has been proven that the transfer of cryopreserved embryos promotes pregnancy with almost the same chances as with the transfer of fresh ones.

Indications for cryopreservation

This complex procedure is carried out in cases where a woman:

• wants to become a surrogate mother;
• has genetic diseases and before the embryo transfer was carried out, as a result of which diseased embryos were weeded out, and the number of healthy ones exceeded 4-6 pieces;
• during the period of embryo transfer, she suddenly fell ill with viral or infectious diseases, which could provoke a spontaneous abortion or the birth of a child with various pathologies;
• wants to get pregnant again after a while;
• I've already done IVF, but it didn't work.

Embryo cryopreservation: pros and cons

This procedure has certain advantages. If a woman is infertile, then she can hope for a second pregnancy. Cryopreservation during repeated pregnancy significantly reduces the burden on the woman's body, because she no longer has to take large amounts of medication and undergo an ovarian puncture. This procedure allows you to significantly save money during repeated IVF, because you no longer have to pay for hormone therapy and egg retrieval.

The chances that a second pregnancy will occur increase significantly, since the eggs are not only fertilized, but also began to divide, which does not always happen during IVF. The procedure using cryopreserved embryos does not allow development. This method also gives other couples a chance to become parents, since frozen embryos can be used as donors.

Thus, cryopreservation has quite a lot of advantages. But still, the procedure using cryopreserved embryos has one significant drawback. It lies in the fact that the percentage of loss of embryos during their freezing and thawing is quite high.

How is cryopreservation carried out?

Required Medications Before Embryo Transfer

In order for the uterine mucosa to be ready for transfer, and the embryo to take root well, doctors prescribe various drugs containing the female hormone for this. Therefore, we will try to answer the question of what medications to take before transferring cryopreserved embryos.

Progesterone preparations prepare the uterine mucosa well, as a result of which the embryo successfully takes root. Such medicines include "Duphaston" and "Utrozhestan". Proginova tablets also help prepare the uterus for embryo transfer.

How is the transfer of thawed embryos carried out?

Embryo transfer is carried out after menstruation occurs after an unsuccessful IVF attempt. The replanting of the blastocyst and crushing embryos into the uterus usually occurs on the day the embryos are thawed.

Embryo transfer and replanting after cryopreservation occur in a natural, stimulated cycle or a cycle with hormone replacement therapy. This allows you to hope for the onset of a long-awaited pregnancy.

The result of the transfer depends on the following factors:

• woman's age;
• properly conducted drug therapy;
• the number of implanted embryos;
• the number of complications during previous pregnancies.

During freezing, the shell of the embryo usually thickens, so before transferring it to the uterus, hatching is carried out, that is, its shell is notched.

Possible outcome of freezing and thawing embryos

It is possible that embryos, after being frozen and then thawed, will be completely unsuitable for transfer due to their destruction. In this case, the transfer will not be carried out.

Preparing the uterine mucosa for replanting, a hormonal analysis is carried out, which will indicate its condition. If for some reason deviations of hormonal parameters from normal have occurred, the transfer procedure is canceled, because the uterine mucosa will be unprepared. In this case, wait for the next cycle, in which the endometrium is re-prepared.

Is it possible to cryopreserve embryos more than once?

This is possible if a large number of embryos were frozen at an early stage of development, after which almost all of them were thawed. Having chosen the best specimens for replanting, the rest are frozen again. The transfer of these doubly cryopreserved embryos promotes the development of pregnancy, but still some factors reduce the successful outcome.

Can cryopreservation affect the development of children?

Parents are very concerned about how a child will develop from a cryopreserved embryo. Special studies were carried out to establish mental, physical, intellectual deviations in the development of such children. The results failed to reveal any abnormalities. The percentage of children with pathologies born from cryopreserved embryos did not exceed the percentage of children with pathologies born as a result of natural conception.

Cost of the procedure

Many women, as well as married couples, are interested in the question: how much does cryopreservation of embryos cost? The cost of the entire cycle, in which frozen material is used, will be several times lower than the amount that the repeated full IVF protocol will cost. The cost of the service depends on how long the cells will be stored in cryostorage, whether donor material was used, on the method of freezing, the number of stored embryos.

In our country, the cost of cryopreservation ranges from 6 to 30 thousand rubles. You will have to pay 1,000 rubles for storing embryos for a month, and 10,000 rubles for a year. If the biomaterial is placed in a separate cryostorage, then the cost of storage for one month is 4 thousand rubles.

Conclusion

Thus, we can conclude that cryopreservation helps many women get pregnant after an unsuccessful IVF attempt and does not affect the health of the newborn in any way. Many couples believe that this procedure is very useful as an assistive technology in the IVF protocol, helping them to additionally secure themselves.

In most IVF programs, superovulation is stimulated. The goal of this procedure is to obtain as many eggs as possible. In the natural cycle, only one oocyte matures in a woman. But in a stimulated one there can be 10-20 or more.

After the eggs are fertilized, they become embryos. Not all, but many survive to transfer. But doctors only transfer 1 or 2 embryos. More - only in exceptional cases, to avoid an increased risk of multiple pregnancy. In 60% of cases, “extra” embryos remain. They are usually frozen so that they can be re-transferred in the next cycle if there is no pregnancy after the first attempt.

The main advantage of frozen embryo transfer is that no re-stimulation of superovulation is required. A woman does not have to buy drugs, make painful injections, and sometimes endure side effects. At the same time, the probability of pregnancy in a cryocycle is higher than in a fresh one, due to the possibility of choosing the ideal day for transfer, based on the degree of readiness of the endometrium.

They freeze not only embryos, but also eggs. This is done to save them for the future. It is likely that in a few years a woman will want to have children again, but her ovaries will no longer function by this time. Thanks to the timely created stock of frozen oocytes, you can get pregnant at almost any age, even after the onset of menopause.

Indications

Not all patients of reproductive clinics require cryopreservation of embryos. This procedure is not cheap. Not only the freezing is paid, but also the subsequent defrosting of the embryos. In the case of long-term storage, payment is made for each month or year, as long as the embryos are frozen after cryopreservation.

Therefore, cryopreservation is carried out only in those cases when it is really necessary. These are the following situations:

If the embryos are disposed of, this means that the woman does not have a safety net in case of failure. Her chances of getting pregnant after one transfer are at best 50/50. At the same time, when performing IVF embryo freezing, it will be possible to try to do the transfer again if the first time is unsuccessful.

It is cheaper and safer than re-stimulation. In addition, when embryo freezing is performed during IVF, treatment is faster. It is undesirable to stimulate the ovaries for two cycles in a row; you have to take breaks in treatment. But the transfer after cryopreservation of embryos is completely safe. It can be carried out at least every cycle.

For such cases, cryopreservation of embryos can be used. You can freeze them in any amount - as much as you can get after puncture and fertilization of oocytes. After cryopreservation, embryos are stored indefinitely. You can become pregnant with a genetically related child even 5-10 years after your own supply of eggs is completely depleted.

Thus, if the doctor sees a threat of hyperstimulation, his task is to ensure that the woman does not become pregnant in this cycle, because this is dangerous for her health. This is not at all difficult to achieve: it is enough to cancel the embryo transfer. What to do with them? Of course, freeze embryos during IVF. They can be transferred to the next cycle, when the “hormonal storm” stops.

In this case, the doctor may consider it appropriate to freeze the embryos during IVF. Cryopreservation allows you to choose the ideal day for transfer in the next cycle, when the chances of pregnancy reach 40-50%. This approach will save embryos and reduce the amount of hormonal stimulation.

1. Surplus embryos after egg fertilization. If a lot of oocytes were received, a high percentage was fertilized, then a large number of embryos are also obtained. Only one or two are used for transfer. What to do with the rest? There are two options: dispose or freeze.
2. Low ovarian reserve. It is likely that you will become pregnant after IVF and have a baby. But if you have a low ovarian reserve, this pregnancy will likely be your last. If after 2-3 years you come back to the fertility clinic and start treatment, it may turn out that your own eggs are no longer there.
3. Complications during stimulation. If the dose of gonadotropins is too high for you, it is fraught with ovarian hyperstimulation syndrome. It may be early or late. The early one is usually not dangerous and proceeds in a mild form. Late is often more serious, sometimes requiring hospitalization. It develops during pregnancy.
4. Low predicted efficiency of fresh transfer. In each cycle, the doctor must achieve the maximum chance of pregnancy. But sometimes he sees that the chances of success are low. The reproductologist makes such conclusions based on the structure of the endometrium and the level of progesterone in the blood. The "implantation window" may close prematurely. Then the probability of pregnancy in the current cycle with the transfer of one embryo does not exceed 15%.

Embryo classes

In the embryological laboratory, it is customary to divide embryos according to quality. This allows you to choose the best among them for transfer, as well as predict the likelihood of pregnancy. To increase it, the doctor may decide to transfer 2 embryos, and not one, if they are not of high enough quality.

Each is assigned a certain class, which is indicated by a letter of the Latin alphabet. Class A is considered the highest. Such embryos are transferred first. With their transfer, the likelihood of pregnancy will be as high as possible. The worst is class D. They try not to freeze them, but transfer them to the uterus only if there are simply no others.

Some women fear that if a poor-quality embryo is transferred, the pregnancy may proceed with complications, or a defective child will be born. There are no grounds for fear. If the embryo has genetic defects, then it will simply die, and the woman will not become pregnant. If it develops, then the risk of spontaneous abortion, chromosomal or genetic defects is not higher compared to high quality embryo transfer. This is due to the fact that at the initial stage of development, all the cells that make up the embryo are the same. Only their number differs.

Freezing methods

Freezing of embryos is carried out in two ways: fast and slow. Slow freezing is an outdated method that is used only in the most backward clinics. It has more historical than clinical significance. Gradual freezing has a number of disadvantages:

• some of the cells die;
• the quality of the embryos is lost;
• there is a risk of death during defrosting, so there are times when a woman came to the clinic for transfer, but there is nothing to transfer.

During slow freezing, the blastocyst is prepared in a special way. The water in it is changed to a cryoprotectant substance. This is necessary so that the cell is not damaged by ice crystals. The treated embryos are placed in plastic tubes and frozen at low temperature.

Vitrification is a method used in most reproductive centers. Instant freezing allows you to bypass the stage of crystallization, immediately turn water into ice. Therefore, the cell is not damaged. All frozen embryos survive, there are no losses at all. Cell quality is not reduced. Therefore, when performing a cryoprotocol, the probability of pregnancy is much higher than in the case of slow freezing.

Storage of cryoembryos

Often women ask: how long can embryos be stored frozen? Will they deteriorate over time? Is it possible to freeze cells today and unfreeze in 10 years?

It is believed that frozen biomaterial can be stored indefinitely. What is meant by "unlimited"? Of course, no one will save embryos for 100 years. It is understood that during the period when a woman still has at least a theoretical opportunity to become pregnant, and even much longer, the embryos retain 100% quality. For several decades, they definitely will not deteriorate. To date, many cases have been recorded when women became pregnant after the transfer of embryos stored for more than 10 years.

The preparation for frozen embryo transfer is the same as for regular IVF. A woman must get rid of bad habits, follow a certain diet so that her weight is optimal for transfer. It is necessary to take folic acid for three months before replanting and after it.

The transfer can be carried out both in a natural cycle and after a cryoprotocol with pituitary blockade, when the maturation of the endometrium is achieved by administering hormonal preparations. Frozen embryos after IVF behave in the same way as those obtained after ovarian stimulation. They are able to divide, develop, implant normally.

Many are interested in how frozen embryos take root. Of course, it depends on their quality. If a woman uses frozen embryos during IVF, the chances of getting pregnant are even higher than in a fresh cycle - this has been proven by research in the field of ART. Moreover, when using cryoembryos from a donor egg, the survival rate increases by 3-6%.

How to find out where you can freeze an egg in Moscow? This can be found on the websites of IVF clinics or the forum. Many clinics have their own bank for storing embryos, sperm, and oocytes. But before you go there, you should ask what percentage of frozen embryos they have viable after freezing.

Cryopreservation of oocytes, sperm and embryos is what is used in modern reproductive medicine and allows solving the problem of infertility of various origins. Cryopreservation portends great prospects, but many patients have to deal with this procedure today.

What is cryopreservation?

Cryopreservation is the storage of biologically active objects and organisms at a low temperature with the subsequent restoration of their functions after defrosting. Storage at a low temperature stops all biological processes and thus contributes to the preservation of all the qualities of embryos and sperm. Modern cryopreservation has taken a step forward: if with the old method the biomaterial was easily damaged by ice crystals, today the freezing of embryos and sperm is carried out in an accelerated mode and allows you to save all the functions of the material. This method is called "vitrification" and differs from slow freezing in that the material is in a special liquid containing glucose, which does not crystallize and thereby reduces the likelihood of damage to the material.

Advantages and disadvantages of methods

Of course, cryopreservation of sperm and embryos are different procedures, each of which has its pros and cons. However, modern cryo-freezing technologies have reached the peak of perfection: children born as a result of the use of frozen material are no different from those that appeared naturally.

Sperm cryopreservation

Cryopreserved sperm is a demanded material for artificial insemination (IUI and IVF). Sperm cryopreservation is carried out in the laboratory of reproductive medical centers. Donor frozen sperm is stored in quarantine for up to six months after freezing: in this way, possible defects in the material can be detected. Therefore, the probability of pregnancy using the husband's sperm is much lower if this condition is not met. Thus, the storage time of frozen semen may affect the effectiveness of the procedure.

Cryopreservation of sperm is indicated not only for artificial insemination, but also before radiation or chemotherapy, as well as during harmful work of a man. This will avoid negative consequences for the health of offspring and become a happy father at a more convenient moment in life. Sometimes the choice in favor of sperm freezing is made after they find out how much it costs. The procedure for collecting and freezing sperm is simpler than similar manipulations with embryos that are sensitive to external stimuli.

Embryo cryopreservation

Usually cryopreservation of embryos is carried out during IVF, when after fertilization there is a lot of unclaimed material within the treatment cycle. In this case, at the request of the couple, the healthiest embryos are selected for further storage and possible use. Since the cost of freezing embryos is lower than the cost of a second IVF cycle, it is more profitable to carry out a cryopreservation procedure for the material remaining during IVF: in the future, this will increase the chances of a successful pregnancy.

Recent studies have shown that frozen embryos are more viable in IVF than "fresh" material. In order for the embryo to retain its functions, cryofreezing must be carried out at a certain stage of its development. Embryos are preserved at the zygote stage, 2, 4 or 6 cells, blatocyst. Otherwise, the embryo will die.

How long frozen embryos are stored depends on the wishes of the patients. They can be stored almost indefinitely. After cryopreservation, the transfer of a thawed embryo for IVF can be carried out at any time, this does not affect the effectiveness of the procedure.

The thawing of embryos after cryopreservation occurs as follows: the samples are removed from liquid nitrogen and thawed at room temperature. Replanting is done on the day of defrosting or a day later, depending on the stage of embryo development at the freezing stage.

How is material frozen?

Modern medicine has almost completely switched to the quick freezing method, since slow freezing is less effective. Freezing of embryos and sperm is carried out in the laboratory and includes two main stages.

Material preparation

The most viable embryos or active spermatozoa are selected. Sperm is simultaneously cleaned of proteins and other impurities, resulting in a concentrated sample of it, effective for the upcoming fertilization. Embryos are examined for the presence of mesoderm and other components necessary for the further development of the fetus.

cryofreeze

Material samples are placed in a cryobank, where they are frozen in liquid nitrogen. Sperm after preparation is placed in special containers called "straws", and sent to the freezing procedure, first at a temperature of -20 degrees C, then -196 degrees. C. Freezing embryos is especially difficult because they are made of water and can be damaged by the formation of ice crystals. How the embryo is frozen directly affects its viability in the future: vitrification involves ultra-fast freezing in a jelly-like medium without damaging the material.

Which is better: cryo-freezing of sperm or embryo?

The appropriateness of each procedure is determined by its purpose and circumstances. Both sperm and frozen embryos can be stored indefinitely, but the greatest risk of material loss during thawing is in embryos, and sperm after freezing is able to fully retain its functions. Freezing sperm is cheaper and applicable if the woman's eggs for some reason are not capable of fertilization. Freezing the embryo is advisable after the IVF procedure.

If we compare the use of frozen sperm or embryos with the natural process, there are other advantages: future parents can hope for the birth of healthy children, since careful selection and preparation of material for artificial insemination minimizes all possible risks.

Price policy

Prices for cryopreservation of sperm and embryos in St. Petersburg are determined by the status of the clinic and the method of freezing. The cost of freezing embryos during IVF depends on the individual parameters of the procedure, the cost of cryopreservation in St. Petersburg, as a rule, corresponds to the status of the reproductive center and the qualifications of the specialists working in it. You can get acquainted with the prices for freezing sperm and embryos at the Genesis reproduction center on our website.

In most ART cycles, superovulation is stimulated to produce a large number of eggs, so there are usually a large number of embryos. Since usually no more than three embryos are transferred into the uterine cavity, many patients have “extra” embryos after the transfer.

These "extra" embryos can be cryopreserved (frozen) and stored for a long time in liquid nitrogen at -196ºС. Subsequently, they can be thawed and used for the same patient if pregnancy does not occur in the IVF cycle, or if after the birth of the child she wants to have more children. Thus, she can again go through the cycle of embryo transfer without being subjected to superovulation stimulation and ovarian puncture.

Embryo cryopreservation is one of the well-established methods of assisted reproductive technologies. The first child after a frozen embryo transfer was born in 1984. Most IVF clinics practice cryopreservation of embryos remaining after an IVF cycle for subsequent transfer to the uterus.

The chances of pregnancy after thawed embryo transfer are lower than with fresh embryo transfer. However, reproductologists strongly advise all their patients who have “extra” embryos to carry out their cryopreservation. A cycle of cryopreservation and transfer of thawed embryos is much cheaper than a new IVF cycle, and the presence of frozen embryos is a kind of "insurance" for patients in case pregnancy does not occur. However, since it only makes sense to freeze good quality embryos, cryopreservation is a "bonus" that only about 50% of IVF patients receive.

Approximately half of good quality embryos survive the freeze-thaw cycle. The risk of developing congenital pathologies of the fetus does not increase with cryopreservation of embryos.

Benefits of Embryo Cryopreservation

• Allows you to maximize the chances of pregnancy after IVF and prevent the death of normal viable embryos left after an IVF cycle. This is the most important advantage of cryopreservation. About 50% of patients may have additional embryos for cryopreservation. The efficiency of thawed embryo transfer is constantly growing, approaching the efficiency of "fresh" IVF cycles.
• Cryopreservation of all embryos for future uterine transfer may be recommended for women at increased risk of developing severe ovarian hyperstimulation syndrome after superovulation induction in an IVF cycle.
• IVF cryopreservation of embryos is recommended in cases where the likelihood of embryo implantation is reduced, for example, in the presence of an endometrial polyp, insufficient thickness of the endometrium at the time of embryo transfer, dysfunctional bleeding during this period, or illness.
• With difficulties with the transfer of embryos in the IVF cycle, for example, stenosis of the cervical canal (the inability to pass through the cervical canal due to the narrowing of the canal, the presence of scars in it, etc.).
• Embryo freezing during IVF can be included in the egg donation cycle, if for some reason it is difficult to synchronize the menstrual cycles of the donor and recipient. In addition, in some countries it is mandatory to cryopreserve all embryos derived from donor eggs and quarantine them for six months until the donor re-tests negative for HIV, syphilis, hepatitis B and C.
• After the IVF cycle has ended with the birth of a child, and if the spouses do not want to have more children, the frozen embryos can be donated to another infertile couple.
• Before chemotherapy or radiotherapy for cancer.

How are embryos frozen and thawed?

Embryos can be frozen at any stage (pronuclei, cleavage embryo, blastocyst) as long as they are of good enough quality to survive the freeze-thaw cycle. Embryos are stored individually or in groups of several embryos, depending on how many embryos are planned to be subsequently transferred to the uterus.

Embryos are mixed with a cryoprotectant (a special environment that protects them from damage during freezing). Then they are placed in a plastic straw and cooled to a very low temperature using a special program freezer or the method of ultra-fast freezing (vitrification). Embryos are stored in liquid nitrogen at -196°C.

During defrosting, the embryos are removed from liquid nitrogen, thawed at room temperature, the cryoprotectant is removed, and the embryos are placed in a special medium.

If the embryos were frozen at the cleavage or blastocyst stage, they can be thawed and transferred to the uterus on the same day. However, if they were frozen at the stage of two pronuclei, then they are thawed the day before the transfer, cultured for a day to assess their fragmentation, and transferred to the uterus at the stage of 2-4 cell embryos.

How long can frozen embryos be stored?

Frozen embryos can be stored for as long as required - even several decades. When they are stored in liquid nitrogen, at a temperature of -196ºC, all metabolic activity of cells at such a low temperature stops.

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What is the survival rate of embryos after freezing and thawing?

Not all embryos tolerate the freezing and thawing process well. In a clinic with a well-established cryopreservation program, the survival rate of embryos is 75-80%. Damage to embryos occurs as a result of cryopreservation, but not during the period of storage of embryos, but during their freezing and thawing. Therefore, it may be necessary to thaw several embryos in order to obtain two or three good quality embryos for transfer to the uterus.