Vitrification - Flash Freezing
Most of us are familiar with the concept of flash freezing. Fresh foods are exposed to sub-zero temperatures suddenly and they become frozen within minutes. When the items are defrosted, then tend to react more like fresh foods because the process happened so quickly the goods weren't able to absorb a lot of water - they didn't become soggy.
What's this got to do with IVF? Actually, it has a lot to do with it because the concept is being used more consistently in IVF circles and it's producing good results.
Freezing Human Embryos
Freezing human embryos has been around for more than 30 years, but the results haven't been great. Although conventional cryopreservation techniques are still being used in many IVF centers, many more are using vitrification for freezing embryos and unfertilized eggs. Conventional cryopreservation involves slowly cooling down the embryo until it eventually freezes. The downside to this process is that it causes ice crystals to form inside the cells of the embryo causing damage that result in reducing its viability.
More recently a breakthrough in embryo cryopreservation occurred. It is called vitrification and it is the freezing of the embryo at a rate 600 times faster than conventional cryopreservation. Because this method is ultrafast, there is literally no time allowed for intracellular ice to form. The result is that there is less trauma to the embryo. In conventional (slow) freezing, between 20 and 30 percent of the embryos do not survive the freeze-thaw process, and of those that do make it, there is less than half a chance of generating a pregnancy. Not a very good track record. In contrast, vitrified embryos have a better than 95 percent rate of successful freeze-thaw survival and the pregnancy generating potential is comparable to fresh embryos.
Better Survival Rates
Vitrification in IVF can callow freezing of spare embryos with better post-thaw survival rates and higher pregnancy and live birth rates from frozen embryo transfer cycles. With the current research indicating that allowing the embryos to advance to the blastocyst stage (day 5-6) rather than freezing at the second or third day, those embryos that are chromosomally abnormal are weeded out. The process also means that those embryos that are frozen at the blastocyst stage are more viable than those frozen at an earlier stage.
The use of vitrification has proven to be a major paradigm shift, but it has also improved the potential to bank human embryos safely and reliably. But, that's not the only advantage that has been realized. Vitrification has vastly improved the banking of human eggs that are not fertilized.
New Hope for Cancer Patients
The use of vitrification technology to freeze human eggs is relatively recent and is making big news these days as a way for cancer patients, in particular, to preserve their fertility. It also offers women who want to wait until they are older to have a baby the opportunity to use their own eggs to avoid age-related infertility.
In the past, if a young cancer patient wanted to preserve her fertility while she underwent cancer treatments, most of which can render a woman sterile, she could freeze fertilized embryos - and in most cases that was only viable using donor sperm to fertilize the eggs.
New Options for Age-Related Infertility
Researchers decided to experiment with freezing unfertilized eggs and have been successful. This has provided options to young or single cancer patients who want to have a family. Some cancer treatments bring on early menopause and while not all cancer treatments lead to infertility, many of them do. Additionally, this method is being considered by healthy women who want to wait to have a family - thus actually extending fertility and bypassing age-related infertility. Frozen eggs from a woman's younger years can theoretically be used in future IVF treatments.
There is some controversy when it comes to marketing and offering vitrification to women who want to avoid age-related infertility. The primary argument is that the process is too new and needs more research. On the other side of the coin, fertility doctors have been using the method for embryo freezing and stand with the latest research showing the method is effective.
Fertility treatments enable women who have reproductive issues to have children. There are many different methods of reproductive technology that you can read about in this site.
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