Embryo freezing (cryopreservation) is an essential part of modern fertility treatment. It allows high-quality embryos created during a treatment cycle to be preserved for future embryo transfers. This increases the overall cumulative chance of achieving a pregnancy from a single stimulation cycle.
Thanks to frozen embryos, a new pregnancy can be pursued without undergoing another round of hormonal stimulation or egg retrieval. In connection with Preimplantation Genetic Testing (PGT), embryos are always frozen so that the most viable embryo can be selected once the test results are available.
With current freezing and thawing methods (vitrification), over 95% of embryos remain viable for transfer. A frozen embryo transfer (FET) can be performed either during a natural menstrual cycle or in a cycle supported by hormonal medication. On average, approximately 40% of frozen embryo transfers lead to pregnancy.
In IVF treatment, eggs retrieved from the ovaries are fertilized in the laboratory, and the development of the resulting embryos is monitored for several days.
At the end of the treatment, one high-quality embryo is transferred into the uterus (fresh embryo transfer). In accordance with current medical practice, only one embryo is transferred at a time in fertility treatments to ensure maximum safety.
Other high-quality embryos can be frozen for future use. Embryo freezing improves the cumulative success rate of the treatment, and embryos can be stored safely for several years. If pregnancy does not occur after a fresh embryo transfer, a frozen embryo transfer (FET) can often be performed shortly thereafter without the need for a new hormonal stimulation. Cryopreserved embryos can also be used later when trying to achieve another pregnancy — for example, when planning a sibling pregnancy after a successful treatment.
Vitrification
During fertility treatment, the embryos created are carefully screened to select the best one for transfer into the uterus. One embryo is chosen for a potential fresh embryo transfer, while any other high-quality embryos are frozen in our clinic’s laboratory for future use.
Embryos are cryopreserved using vitrification, a modern and widely used freezing method. During vitrification, the embryo is cooled extremely rapidly, which prevents the formation of harmful ice crystals and helps preserve the embryo’s structure and viability throughout freezing and thawing.
Frozen embryo storage
Frozen embryos are stored in liquid nitrogen at a temperature of approximately –196 °C under strictly controlled conditions. This ensures the safe preservation of embryos for future frozen embryo transfers (FET).
Embryos can remain frozen for several years without any decrease in their viability. This allows patients to plan the timing of their next treatment at their own pace, according to their individual life situation and wishes.
In addition to embryo freezing, vitrification is also used for egg freezing, and it is an established and widely utilized method for both.
Frozen embryo transfer can be scheduled either:
Current freezing methods are very effective. Over 95% of frozen embryos survive thawing, and approximately 40% of frozen embryo transfers result in pregnancy.
The results are comparable to or even better than fresh transfers, especially when embryo quality is high and the uterus is receptive.
Success depends on several factors, including:
If you are considering fertility treatment or want to know more about embryo freezing, our experts at Ovumia are happy to help.
Book an appointment for your first visit and ask more about embryo freezing – we are here to support you on your journey towards your desired pregnancy. During the first visit, an Ovumia doctor will interview the woman or couple, review the information provided in advance, and listen to your wishes.
Yes. Embryo freezing is a well-established and safe part of modern fertility treatment. With current freezing and thawing techniques, the majority of embryos remain viable, and the safety of the treatment is carefully monitored throughout the entire process.
Embryos can be stored frozen for several years. This makes it possible to plan the timing of embryo transfer flexibly to suit one’s personal life situation and family planning goals.
The use of frozen embryos makes it possible to attempt pregnancy without undergoing a new cycle of ovarian hormone stimulation or egg retrieval.
Yes. Pregnancy outcomes are often comparable to those achieved with fresh embryo transfers and, in some situations, may even be better—particularly when the embryo quality is good and the uterine lining has been carefully prepared for the transfer.
In Ovumia, we are always ready to help you!
