EMBRYO FREEZING and PRESERVATION(Cryo = Freezing = Cryopreservation)
It is possible to reach high rates of pregnancy thanks to the method of embryo freezing and thawing having been applied in IVF laboratories for 20-25 years and new techniques developed in recent years.
In our unit, instead of slow freezing method applied previously, a vitrification (fast) freezing method is now being applied.
The embryos are frozen thanks to the chemical substances called cryoprotectant and preserved in personal regions within liquid nitrogen tanks under -196 °C. Whenever desired, these embryos are thawed and transferred into uterus. Within liquid nitrogen, all chemical reactions and cellular activities stop. This is a kind of cellular sleep. The experimental studies show that embryos can be preserved within liquid nitrogen healthily for a long period.
In our unit, embryo freezing (vitrification) is generally performed on the 3rd and 5th day. High quality of frozen embryos has a direct impact on the rate of live returning of embryos during thawing process.
Under Which Conditions Embryos are Frozen?1- After the transfer, the remaining quality embryos can be preserved to be transferred again by freezing instead of disposing.
2- During stimulation of ovaries by drugs, all embryos can be frozen to be used at a later time in the women with the risk of OHSS (ovarian hyperstimulation syndrome).
3- When intrauterine endometrium tissue hasn’t developed sufficiently.
4- In case of intrauterine surgical operations.
5- Embryos can be frozen before cancer treatments which require chemotherapy or radiotherapy.
Advantages of Embryo Freezing for PairsEmbryo freezing in an IVF unit is a crucial issue in terms of its advantages to the pairs. Transferring a few (1-2) embryos in a fresh cycle and freezing the remaining embryos decreases the possibility of multiple pregnancy which is a risky process of pregnancy. It provides the pairs with an opportunity of a healthy pregnancy and birth which is the main purpose.
Thawing and transferring the frozen embryos offers the pairs the chance of pregnancy identical to a fresh trial with lower expenditure. Furthermore, the operations such as use of drugs for long period, oocyte pick-up and ICSI (injection of sperm into oocyte) are not needed anymore. Also, desire for a second baby of pairs who experience pregnancy may be possible with thawing and transferring of frozen embryos.
Preservation Time of Frozen EmbryosThe scientific studies have shown that the frozen embryos provide a chance of healthy pregnancy even if they are thawed after a very long period of 10-15 years. However, the frozen embryos can be preserved within liquid nitrogen only for 5 years in our country in accordance with the relevant regulation of Ministry of Health.
Embryo Freezing Using Vitrification MethodIt has been proven that vitrification freezing method is a superior technique when compared to the other freezing method (conventional slow freezing). When the embryos frozen with this method are thawed, they return alive and healthily at the rate of 90 – 100%. The important point here is whether quality of embryos is sufficient for freezing.
Brussels IVF Unit, like all other IVF techniques, is following all developments in the field of vitrification method instantly and continuing its scientific studies in order to achieve higher successes. Thanks to our studies, rates of pregnancy as almost high as fresh embryo transfers are obtained with vitrification method in our unit.
When its advantages are taken into consideration, all pairs we find convenient for embryo freezing are notified by our team on the day of transfer and they are recommended to have their embryos frozen.