Frozen Embryo Transfer Cycle (FET)
Frozen Embryo Transfer Cycle refers to the process described below of cryopreserving embryos and transferring them into a uterus that has been prepared for IVF.
What is Embryo Freezing ?
The conventional IVF procedure, which utilizes fertility medications to stimulate ovulation, often results in many embryos. Since the risk of multiple pregnancies increases with the number of embryos transferred, many couples are left with more embryos than necessary or more embryos than can be transferred by law in some countries. In some countries, like the UK, the maximum number of embryos that can be transferred is three. These spare embryos can be discarded, used for research, or they can be frozen and cryopreserved for later use by the same couple or another couple wishing to use a donated embryo.
Who can Benefit from Embryo Freezing ?
Women, who are at risk of developing ovarian hyper stimulation syndrome, following ovarian stimulation for IVF treatment, are advised to freeze all their embryos for consecutive transfer. In some cases when fresh embryo transfer fails, “spare” embryos can be cryopreserved for a second or third trial. Cryopreserved embryos are available for donation to barren couples. In fact, some countries mandate that all embryos resulting from donated eggs be cryopreserved and quarantined for a period of six months until all donor screening tests are complete.
Frozen embryos are just as good as fresh embryos, meaning that pregnancy rates are just as high, and there is no more risk of abnormalities with frozen embryos than fresh, therefore patients are often encouraged to choose the more cost-effective route of freezing their embryos rather than discarding them, as a guarantee in the event that the first embryo transfer fails, or pregnancy is not carried out to term. Using frozen embryos, which can be stored for up to several years, is a much less expensive alternative to starting a new cycle.
How are Embryos Frozen ?
Embryos can be stored in batches of one or more. Like any living tissue, the cells of embryos contain water, which must be removed prior to freezing to prevent ice crystals from forming and causing the embryos to burst. The embryos are then gradually mixed with a cryoprotectant fluid that does not form ice crystals, and then put in a plastic straw or a glass ampoule. The mixture is stored in liquid nitrogen at a very low temperature using a specialized programmable machine. Temperature is crucial since embryos are subject to metabolic change.
How are Embryos Thawed ?
During the thawing process, the frozen embryos are removed from the ampoule and brought to room temperature. The cryoprotectant fluid is gradually removed and diluted with water, eventually allowing more water than cryoprotectant. This process must be done very diligently as the embryo can burst if the water is rushed into the cells at once. After the embryos are brought to room temperature, they can be transferred to the recipient mother.
Frozen Embryo Transfer
Also refers to the process of cryopreserving embryos and transferring them into a uterus that has been prepared for IVF.
The main benefit of embryo freezing is that it allows the replacement of embryos in later treatment cycles without the need for ovarian stimulation and egg collection.The survival rate of frozen - thawed embryo in our program is around 90 - 95 % and 85 % for further embryo development. The replacement of frozen embryos is preferably carried out after treatment with hormone replacement therapy. The artificial cycle has been shown to be beneficial both in terms of results and in keeping monitoring to a minimum. The actual day of transfer can also be planned in advance for optimum convenience.
Coping with Infertility
We understand that anticipating the results of IVF can be grueling and stressful on couples, and the possibility of an unsuccessful outcome can be overwhelming. In spite of this, it is important that couples maintain a healthy and clear psyche. Plenty of rest and avoiding stress are highly recommended before, during and after your trip. Keep in mind that you are traveling, which can add more stress on the body. Drink lots of water and try to obtain ample Vitamin D from the sun and fresh air to conquer jetlag.