What is cryopreservation?

During IVF cycles, multiple eggs mature, resulting in a significant number of embryos following fertilization. Given that no more than two embryos are typically transferred into the uterine cavity, many patients may have additional embryos that can be cryopreserved (frozen) and stored long-term in liquid nitrogen at a temperature of -196°C. These frozen embryos can be thawed and used for the same patient if pregnancy does not occur during the current IVF cycle or if the patient decides to have more children after a successful birth.

Indications for cryopreservation:

Vitrification can substantially enhance the likelihood of achieving pregnancy following IVF and prevent the loss of viable embryos that remain after the IVF cycle. This represents the most significant advantage of cryopreservation.

Freezing all embryos for future transfer into the uterine cavity may be recommended for women who have an elevated risk of developing severe ovarian hyperstimulation syndrome after undergoing superovulation induction in the IVF cycle. It can also be recommended for patients before undergoing radiotherapy or chemotherapy for the treatment of oncological diseases.

Embryo vitrification is indicated in all cases when the likelihood of successful embryo implantation in the uterine cavity is reduced. This includes scenarios such as the presence of an endometrial polyp, inadequate endometrial thickness at the time of transfer, and issues related to dysfunctional bleeding. Additionally, it can be considered in cases where difficulties arise during embryo transfer in the IVF cycle due to the inability to pass a catheter through a narrowed cervical canal into the uterine cavity, such as cervical canal stenosis.

Cryopreservation can be integrated into the egg donation cycle when, for various reasons, synchronizing the menstrual cycles of the donor and recipient proves challenging. In such cases, the patient can have a cryopreserved (thawed) embryo transferred into the uterine cavity without the need for repeated superovulation stimulation and ovarian puncture.

The likelihood of achieving pregnancy following the transfer of thawed embryos is higher than when transferring fresh ones. Therefore, we highly recommend patients, especially those who have surplus embryos, to opt for cryopreservation using rapid freezing (vitrification). Approximately 50% of IVF patients may have additional embryos suitable for cryopreservation. The process of freezing and transferring thawed embryos is considerably more cost-effective than undergoing an entirely new IVF cycle. Having frozen embryos serves as a form of “insurance” for patients in the event that a pregnancy does not occur.