Preservation of female fertility: vitrification of oocytes


Until recently, preservation of fertility was an option that only men could access through freezing sperm, as the eggs, because of their sensibility, did not get through the freezing process.

Nowadays, preservation of eggs is possible thanks to the appearance of vitrification.

Vitrification is a new revolutionary technique which permits the ultra-quick freezing of gametes and embryos using high concentration of cryoprotective substances, which prevent the formation of crystals inside the cell.

In this way, it is possible to keep oocytes frozen at a low temperature for indefinite periods of time and to obtain high survival and pregnancy rates once devitrified.

The users of this technique should start a hormone treatment to stimulate the ovaries. The goal of this treatment is to get the growth and ripening of an adequate number of eggs, which will be subsequently removed and transferred to the laboratory through a simple surgical procedure (which takes place in an operating room), called funicular puncture.

Once in the laboratory, using vitrification technique, oocytes will be frozen and stored in the egg bank for an indefinite period of time, until their owner determines their destiny.

The options established by the law are as follows:

– To thaw and fertilize them with the semen sample of the corresponding partner, or with sperm donor if it were the case, to subsequently transfer the embryos obtained.
– To donate them to the egg bank so that they can be used by other women with similar characteristics to those of the donor.
– To donate them to the science.
– To thaw them taking the law into account.

This whole procedure is a safe treatment and with minimal risk to the health of the patient. Complications that may arise such as vaginal bleeding, abdominal swelling or pain and hyperstimulation of the ovaries, if they do occur, are minimal, as once the eggs have been removed, appropriate check-ups are carried out to ensure a proper health state and a good patient evolution.

As regards the success rate of this technique, 85% of the vitrified eggs survive the process successfully, and out of these, 75% are correctly fertilised, giving rise to embryos of good quality with a high embryo implantation potential and pregnancy.

Although nowadays success is not guaranteed with any existing assisted reproduction technique, vitrification is a good alternative and a glimmer of hope to all the women who wish to preserve their fertility.


The indications for the technique are the following:

– Looking ahead: Young women who for social reasons delay their maternity but decide to freeze eggs to prevent possible fertility problems.

– Medical cause: Women with oncological diseases or not , whose treatment compromises the quality of the oocytes or their fertility.

– Complementary technique to Reproductive treatments (IVF): Women with a low response who use vitrification to get an optimal number of eggs.

And also in the opposite case: Women with an exaggerated response who froze their eggs not to generate supernumerary embryos or to use them in future cycles when the patient will be better prepared.