Embryo freezing is a process that permits individuals to store embryos for sometime in the future. An individual can also freeze eggs, which are not fertilized. An embryo is developed after fertilization and the cells begin to divide. Physicians can freeze and store unused embryos (fertilized eggs) created during IVF, which may include intracytoplasmic sperm injection (ICSI), using a process called cryopreservation.
Fast cooling convention (vitrification) includes media containing a higher concentration of cryoprotectants and has a moderately lot more limited freezing time. The fundamental concern when freezing an embryo is the development of ice between the cells. This can be effectively avoided by a profoundly skilled embryologist.
Slow cooling includes seeding where the cryopreservation straw is physically moved by cold forceps dipped in liquid nitrogen further away from the embryo to start ice development which spreads to the rest of the solution containing the embryos. This prevents harm to the embryos. Most centers today apply vitrification for freezing embryos.
During this method, the frozen sperm/oocytes/embryos are thawed (de-frozen) to room temperature, noticed for further development, and afterward moved into the patient’s uterus after stimulating endometrial development. At the time of embryo substitution, the straws are taken out from the liquid nitrogen and set in a water shower at room temperature before re-hydrating with unique media. Toward the finish of re-hydration, the embryos are cultured in media inside the carbon dioxide incubators and permitted to grow further either to day 2 or blastocyst prior to transfer.
Research shows that the freezing and thawing of embryos does not harm subsequent babies made through IVF. The length of time the embryo was stored does not affect IVF success rates.
With improving technology, the difference in pregnancy rates between the frozen embryos and fresh is negligible. In addition, the stimulation process with frozen embryo transfer is gentler, with hormone levels closer to normal in the woman, which may also improve pregnancy rates.
Any ice crystals formed during the slow freeze process may cause damage to an embryo while thawing. This is one of the reasons vitrification is the preferred cryopreservation technique. Research shows that there is no increase in the risk of birth defects among children born from frozen embryos compared with normal births.