The first baby born from a frozen – thawed egg after fertilization in the laboratory under assisted reproduction was reported in 1986. However, despite the great importance of this scientific breakthrough, the success rate was so low that the freezing of eggs in everyday practice was prohibitive.
Since 1986, the number of births from cryopreserved eggs has been rapidly increasing thanks to the major advancements made in the field of cryobiology in combination with the IVF.
More specifically, three technological breakthroughs in assisted reproduction (microinjection, cryoprotectants and vitrification technique) have changed the data reported so far. Now, young women with cryopreserved eggs have approximately the same chances to achieve pregnancy as women who undergo conventional IVF.
Many studies have been published in recent years on the efficiency of vitrification of both eggs and embryos. More specifically, the vitrification method involves the use of cryoprotectants in high concentration and the rapid cooling rate of eggs at 20.000 °C / min.
One of the main advantages of the vitrification technique is the prevention of intracellular ice crystal formation since the cell is dehydrated before freezing.
Of utmost importance to the survival and fertilization of eggs after freezing is their pre-freezing quality. If the quality of the eggs (which is related to the age of the woman) is good, then the survival rate after thawing can reach 96%, their fertility rate 80% and the clinical pregnancy rate at 37.5% per cycle.
In other words, success rates do not differ from those in convention cycles with fresh eggs. Therefore, higher success rates are observed in women of younger age with good quality eggs while in women of older age (>40 old), success rates decrease dramatically due to the expected low quality of eggs.
It is important to provide accurate information to women who choose to freeze their eggs.
Some recommendations of the European Society of Human Reproduction and Embryology (ESHRE) worth mentioning include:
When would it be best to freeze a woman’s eggs:
Therefore, freezing a woman’s eggs at the age of 30 helps to preserve her “fertility frozen in time” until she chooses to have a child with the right partner. In recent years, the freezing of eggs for social reasons (social freezing) is becoming more and more frequent in both the USA and Europe.
The freezing of eggs is a new technique of assisted reproduction providing the opportunity to women to freeze their eggs and choose when they would like to use them.
This technique also enables women who need medical treatment, such as chemotherapy, to freeze their eggs before treatment and use them when their health permits.
In recent years, vitrification has revolutionized the field of egg cryopreservation. According to recent data, combined with the results of our clinic, we expect a survival rate of >90% while pregnancy rates resemble those in the cycle where fresh eggs are used. Egg cryopreservation is therefore an affordable option for all women.