Many couples dream of being happy parents, but a diagnosis such as infertility of one or both partners negates all hope. In this case, in vitro fertilization (IVF) comes to the rescue - a procedure that helps infertile couples give birth to a long-awaited baby. It is necessary to carefully prepare for it, because a hormonal explosion in the body of a woman leads to increased production of eggs.
After this, the ovaries are punctured, that is, a special needle is taken from them to take the fluid 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 is waiting for the onset of pregnancy.
But it happens that in the test tube in which the eggs were fertilized, more embryos formed than was necessary. In this case, doctors advise to carry out such a procedure as cryopreservation of embryos. They may be needed if the first IVF procedure was unsuccessful or a woman later wants to give birth to a second child.
What is cryopreservation?
Cryopreservation of embryos is a procedure for their safe freezing with placement in liquid nitrogen, which has a temperature of 196 degrees below zero. In this case, all biochemical processes stop, that is, the embryo stops in development, but if thawed, it remains viable.
Many women fail to get pregnant using 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 stimulating the ovaries, 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 was proved 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 transplanting embryos, underwent preimplantation genetic diagnosis, as a result of which sick embryos were eliminated, and the number of healthy ones exceeded 4-6 pieces;
- during an embryo transplant, she suddenly became ill with viral or infectious diseases, which could provoke spontaneous abortion or the birth of a child with various pathologies;
- wishes to conceive again after some time;
- already done IVF, but unsuccessfully.
Embryo Cryopreservation: Pros and Cons
This procedure has certain advantages. If a woman is infertile, then she can hope for a second time pregnancy. Cryopreservation during repeated pregnancy significantly reduces the burden on the woman’s body, because she no longer has to take drugs in large quantities and undergo ovarian puncture. This procedure allows you to significantly save on repeated IVF, because you don’t have to pay for hormone therapy and egg collection.
The chances that a second pregnancy will occur significantly increase, since the eggs are not only fertilized, but also began to share, which does not always happen during IVF. The procedure using cryopreserved embryos does not allow the development of ovarian hyperstimulation syndrome. This method also gives other couples a chance to become parents, as frozen embryos can be used as donors.
Thus, cryopreservation has quite a few 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?
From the fertilized eggs, the doctor selects the highest quality and healthy embryos. Then they are placed in a test tube and treated with a cryoprotectant that protects them from damage.
Each such tube is placed in microcontainers, which are plastic tubes that are labeled, and up to 5 embryos can be stored in them. After that, they are placed in a cryobank and cooled by ultrafast or slow freezing. In the cryobank, storage of cryopreserved embryos lasts from a month to several tens of years, depending on the desire of the woman. The main condition of the cryopreservation process is good quality and high viability of the embryos.
How does the process of thawing embryos?
Embryos are thawed at room temperature. For this, the tube in which they are located is removed from the cryoprotectant and transferred to a special environment. As soon as the embryo is completely thawed, it is transplanted into the uterine cavity.
After cryopreservation, the embryo is transplanted in a natural or stimulated cycle, as well as in a cycle with hormone replacement therapy.
Essential medicines before embryo transfer
In order for the uterine mucosa to be ready for transfer, and the embryo to take root well, doctors prescribe for this purpose various medicines containing female hormone. Therefore, we will try to answer the question of which drugs to drink before transferring cryopreserved embryos.
Progesterone preparations are well prepared for the uterine mucosa, as a result of which the embryo successfully survives. These drugs include Dufaston and Utrozhestan. Proginova tablets also help prepare the uterus for embryo transfer.
How is the transfer of thawed embryos?
Embryo transfer is carried out after menstruation occurs after a failed IVF attempt. The implantation of blastocysts and crushing embryos into the uterus usually occurs on the day of embryo thawing.
Transfer and implantation of the embryo after cryopreservation occurs in a natural, stimulated cycle or cycle with hormone replacement therapy. This allows us to hope for a long-awaited pregnancy.
The result of the transfer depends on the following factors:
- woman's age;
- correctly 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 performed, that is, its shell is incised.
Possible outcome of embryo freezing and thawing
It is possible that the embryos, after they are 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 implantation, 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 mucous membrane of the uterus will be unprepared. In this case, they wait for the next cycle in which the endometrium is re-prepared.
Is embryo cryopreservation more than once possible?
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 selected the best specimens for replanting, the rest are frozen again. The transfer of such doubly cryopreserved embryos contributes to the development of pregnancy, but nevertheless some factors reduce the successful outcome.
Can cryopreservation affect the development of children?
Parents are very worried about how the child will develop from a cryopreserved embryo. Special studies were conducted to establish mental, physical, intellectual abnormalities in the development of such children. The results could not reveal any deviations. 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.
Procedure cost
Many women, as well as couples, are interested in the question: how much does cryopreservation of embryos cost? The cost of the entire cycle in which the frozen material is used will be several times lower than the amount that will cost a repeated full IVF protocol. The cost of the service depends on how long the cells will be stored in the cryostorage, whether donor material was used, on the method of freezing, the number of stored embryos.
In our country, the cost of cryopreservation is from 6 to 30 thousand rubles. For the storage of embryos within a month you will have to pay 1 thousand rubles, for a year - 10 thousand rubles. If the biomaterial is placed in a separate cryogenic storage, then the cost of storage for one month is 4 thousand rubles.
Conclusion
Thus, we can conclude that cryopreservation helps many women become pregnant after an unsuccessful IVF attempt and at the same time does not affect the health of the newborn. Many couples are sure that this procedure is very useful as an assistive technology in the IVF protocol, which helps them to further secure themselves.