There has been a freezing revolution in the IVF lab. Some would say it's a slow revolution, because the technique of vitrification was first described more than 20 years ago, but in the past few years, as demands on embryo freezing have grown throughout the world, more and more IVF clinics are turning to this new fast-freeze technique whose results have been remarkable, to say the least. Vitrification is now the favored freezing method at most of the world's IVF clinics.
The problems of conventional embryo freezing methods:What studies have found was that the ice crystals were damaging some of the embryos. Post-thaw survival rates varied between 50 and 60%, but there was still a significant number which did not survive.
What are the advantages of oocyte or embryo vitrification?
Vitrification is an advanced cell-freezing technique, which allows a higher survival rate after thawing due to the fact that high concentrations of cryoproctectors are used along with reduced volumes and timings. Thus, the formation of intracellular ice crystals is prevented, which are responsible, in most cases, for provoking irreparable cell damage.
The vitrification process is used to freeze oocytes or embryos and it guarantees a survival rate of more than 80%. This technique enables the vitrified oocytes which have survived the thawing process to have similar attributes to fresh ones. They are then able to be fertilized by the spermatozoids. The generated embryos can then be implanted and develop into healthy children.
Typical IVF treatment involves stimulating a woman’s ovaries with hormones to produce eggs which are then collected and fertilised in the laboratory, with one or two embryos being transplanted into the womb two days later. The remaining embryos can be slow-frozen or vitrified, then stored, to be used later if the initial cycle fails.
New studies have provided further evidence that vitrified embryos may be better than fresh for IVF.
FROZEN embryos are more likely to produce successful, complication-free IVF pregnancies than those that are fresh, research suggests.
The studies indicate that using vitrified embryos rather than fresh embryos reduces the risk of stillbirth and premature delivery. The technique allows more embryos to survive the thawing process than the older and more widely used slow-freezing method.
It is unclear why this is the case; there are several theories. Some experts have suggested that when fresh embryos are used women may still be suffering from the effects of the powerful drugs that are used to stimulate the ovaries, temporarily disrupting any IVF attempt shortly afterwards.
The scientists think there could be two reasons for the results. One is that only prime quality embryos are likely to survive the freezing process. The other, more popular, theory is that the womb lining is allowed time to settle down and recover from the rigours of IVF hormone treatment.
Cryopreservation as a process can be divided into two methods: conventional freezing and vitrification.
There are 2 methods of Cryopreservation of your Embryos and Eggs:
Vitrification is fast Freezing and Slow Freezing. Understanding the pros and cons of these processes.
Vitrification is a newer technique which uses ultra-rapid cooling, together with a much higher concentration of cryoprotectants. Vitrification is used for cryopreservation of eggs and embryos , and does not cause damage due to ice crystal formation. Vitrification requires the addition of cryoprotectants prior to cooling. The cryoprotectants act like antifreeze: they lower the freezing temperature. They also increase the viscosity. Instead of crystallizing, the syrupy solution turns into an amorphous ice i.e., it vitrifies.
The three large, independent studies took place in Finland, Australia and the US. The Finnish study found that babies born from fresh embryos were 35 per cent more likely to be premature and 64 per cent more likely to have a low birth weight when compared to those born from vitrified embryos.
Two conditions usually required to allow vitrification are an increase in the viscosity and a depression of the freezing temperature.
At Rotunda Infertility Clinic, we have been using vitrification for a number of years to cryopreserve both embryos and eggs.
When it comes to embryo cryopreservation.
Vitrification has improved potential to successfully bank human eggs. We run a very successful Egg bank at Rotunda fertility Clinic.
Pros of Vitrification technique :
1.This ultra rapid process is so fast that it literally allows no time for intracellular ice to form. As a result, vitrification avoids trauma to the embryo.
2.Vitrified embryos have a better than 95% freeze-thaw survival rate, and a pregnancy generating potential that is comparable to fresh embryos.
3.High survival rate enables us to preserve eggs safely and reliably.
Vitrification is fast freezing and is superior to Slow Freezing of Embryos.
Slow Programmable freezing
1.It causes ice crystals to form within embryo's cells (blastomeres).
2.Unsatisfactory survival rate. Only 50 % of embryo survive.
3.All embryos do not survive the freeze-thaw, and those that do survive have less than half the likelihood of generating a pregnancy as do fresh embryos.
4.Very time consuming. Embryos are slowly cooled using a programmable freezer before they are actually frozen. It takes approx. 2 hours to freeze embryos using this technique.
1.No ice crystals are formed inside cells as freezing occurs ultra rapidly.
2.Optimal survival rate is achieved. About 95% of embryos and eggs survive.
3.Excellent survival of embryos and pregnancy generating potential that is comparable to fresh embryos.
4.Doesn't take much time with this technique. As the embryos are cooled ultra rapidly. It takes approx. 30 min to vitrify 10 embryos.
Cryo Tech Lab products for IVF Lab ,assisted reproduction technologies clinics:Cryo Tech Lab products for IVF clinics for high performance vitrification to assist the Artificial Reproductive Centers in the world in the preservation of oocytes and embryos with more than 99% of survival, increasing their efficiency and success.
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Article By: cryotechindia