IVF Laboratory Procedures Embryo Freezing
(Cryo = Freezing = Cryopreservation)
Thanks to the embryo freezing and thawing method, which has been applied in IVF laboratories for 20-25 years, and new techniques developed in recent years, it is possible to obtain pregnancies at much higher rates.
In our unit, a much more successful vitrification (fast) freezing method is applied instead of the slow (slow) freezing method used in the past.
Embryos are frozen by means of chemicals called cryoprotectants and stored at -196 °C in liquid nitrogen tanks in their private areas. When desired, these embryos are thawed by reverse procedures and transferred to the mother's uterus. All chemical reactions and cellular activities stop in liquid nitrogen. This state is a type of cellular dormancy. In experimental studies, it has been demonstrated that embryos can be stored in liquid nitrogen for a long time in a healthy way.
In our unit, embryo freezing (vitrification) procedure is usually performed on the 3rd and 5th days. The good quality of the frozen embryos directly affects the rate of return of the embryos alive in the thawing process.
In Which Situations Is Embryo Freezing Performed?
1- After the transfer procedure, the remaining quality embryos can be frozen and stored for retransfer instead of being destroyed.
2- All embryos can be frozen a possible need of use later in women at risk of OHSS (overstimulation syndrome) during stimulation of the ovaries with drugs.
3- In cases where the endometrium tissue surrounding the uterus cannot develop sufficiently.
4- In cases where intrauterine surgery is necessary.
5- Embryos can be frozen before cancer treatments requiring chemotherapy or radiotherapy.
Advantages of Embryo Freezing for Couples
Ability to freeze embryos in an IVF unit is an important issue in terms of the advantages provided to couples. Transferring fewer (1 to 2) embryos and freezing the remaining in a fresh cycle reduces the possibility of multiple pregnancy, which is a risky pregnancy process. As the main goal, it provides couples with a healthy pregnancy and birth.
Thawing and transferring frozen embryos provides couples with a chance of almost a fresh attempt pregnancy by spending less. Furthermore, there is no need for long-term drug use, egg collection and ICSI (sperm injection into the egg). Besides, the request for a second child in couples who have achieved pregnancy can be possible by thawing and transferring the frozen embryos.
Storage Duration of Frozen Embryos
Scientific studies revealed that there is a healthy pregnancy chance even when frozen embryos are used after being thawed after a very long time, such as 10-15 years. However, in accordance with the relevant guidelines of the Ministry of Health in our country, frozen embryos can be stored in liquid nitrogen for 5 years.
Embryo Freezing with Vitrification Method
Compared to the other freezing method (conventional slow freezing), the vitrification freezing method has proven to be a much superior technique. When the embryos frozen with this method are thawed, the chance of returning alive and healthy is about 90 to 100%. The point to be marked here is that the quality of the frozen embryos should be suitable for freezing.
Brussels IVF Unit, like all other IVF techniques, immediately follows all innovations in vitrification and continues its scientific studies to achieve higher success. Thanks to the studies we have conducted, we can achieve pregnancy rates almost as high as that of fresh embryo transfers with the vitrification method in our unit.
Considering the advantages it offers, all couples who are assumed to be suitable for embryo freezing by us are informed by our team on the day of transfer and the embryos are recommended to be frozen.