Interest of Automated Oocyte Freezing

In the space of a few decades, oocyte cryopreservation has become established in the world of reproductive biology with the authorization of oocyte vitrification. This ultra-fast manual freezing technique (authorised in France since 2011) is mainly used to preserve oocytes in women who have to undergo a treatment that could potentially cause sterility. A clear improvement in survival rates since the early stages of slow freezing has been observed with vitrification but with fairly heterogeneous results Indeed, manual vitrification remains an operator-dependent technique with a long learning curve and which does not allow an oocyte survival rate of more than 70-80%. The recent marketing of an automatic vitrification machine would make it possible to standardise the whole vitrification process from the contact/exchange of fluids to the sealing of the units, and thus potentially increase the oocyte survival rate. It seems to be in the best interest of women that their ability to conceive be preserved (probably for several years) with the technique that offers the best survival and reproducibility rates. However, no studies have been conducted to assess the impact of such automation on oocyte survival. For this reason the investigators wish to set up a comparative study between the routine, manual technique, and an automated technique (GAVI system), using immature oocytes, not suitable for fertilization, and usually discarded.