The in vitro fertilization program involves the stimulation of ovulation to produce the maximum number of viable eggs. As a result, as a rule, it is possible to obtain more healthy embryos than are necessary for replanting. Many couples decide to save a surplus for repeated IVF protocols in case they are needed. After all, while reproductive medicine does not give a 100% guarantee that pregnancy will occur on the first try. In addition, in the future, the couple may decide to have a second child.
For such situations in modern clinics, a service is available cryo-freezing or conservation biomaterial. At the request of patients, collection and storage of oocytes, sperm and embryos can be performed.
Stages of freezing
First, it is worth understanding what this ART procedure is. Cryopreservation Is a special method of storing biological material for a long time. By exposure to low temperatures in the cells, all vital processes are stopped, but their structure and functions are not disturbed. Such freezing allows in the future to completely restore biological material.
Cryopreservation is carried out in several stages.
- Selection of the best quality embryos.
- Dehydration. This avoids ice crystallization, which is harmful to cells. According to the vitrification method, the embryo is first placed in a buffer mixture for 10 minutes, and then in a cryoprotectant. Its penetrating formula displaces water and protects cells during freezing.
- Embryos are placed in special tubes – cryo-carriers. They are dipped into canisters, and then into Dewar vessels with liquid nitrogen. In these cryo-storage facilities a special temperature regime is observed: -196⁰С.
IVF cryo-embryos allows you to reduce the burden on the female body. There is no need to re-stimulate superovulation. This facilitates the infusion in terms of the state of the endometrium and the hormonal background of the woman. Plus you can do it Cryo-IVF in the natural cycle.
The conservation procedure is available for different types of biomaterial. Embryos are successfully preserved. Also is possible egg freezing. In this case, a woman can postpone pregnancy and at the same time preserve the youth of her reproductive cells. Similarly, frozen sperm. Sometimes cryopreservation is the only way to maintain reproductive health, for example, after treatment with radiation or chemotherapy. Cryopreservation and IVF artificial insemination – methods that give chances in previously hopeless situations.
Vitrification is the most common cryo-technology today. This is the most effective conservation method, in which the biomaterial is cooled ultra-fast – up to 20,000 ⁰C / sec. The cells become glassy, the absence of ice crystallization points in them makes the procedure as safe as possible. Liquid nitrogen does not impair the viability of the embryos. It “stops time” by slowing down all biological processes.
The storage period can be any. 10 years of cryofreezing is a well-known practice, after which a successful pregnancy has been recorded more than once. The efficiency of preservation by vitrification is 98-100%. At the moment, the effectiveness of IVF with cryo-embryos has practically reached the indicators of “fresh” protocols.
Cryopreservation of embryos: pros and cons
The procedure has the following advantages.
- High probability of successful conception. In some cases, cryo-transfer is the only way out.
- No need for repeated stimulation of ovulation. Reducing the load on female hormones allows you to better prepare for a healthy pregnancy.
- Savings on repeated IVF protocols, including the purchase of additional drugs.
- Prevention of ovarian hyperstimulation. This is one of the serious consequences of superovulation.
- Increase in reproductive age. Freezing allows young eggs to be stored for future pregnancy attempts when ovarian reserve is naturally reduced.
- Prevention of infertility as a consequence of cancer therapy.
- Participation in the donor program. A couple who have frozen embryos can always transfer them to other infertile families.
The only disadvantage of the procedure is the lack of knowledge about it in society. Therefore, many do not yet use the services of cryogenic storage, although they need it.