Next Fertility IVF Prof. Zech

Egg Freezing

Cryopreservation of Oocytes

Thanks to advanced technologies available in the field of reproductive medicine, women are being given the chance to freely decide on the freezing and "storing" of some of their oocytes as a precautionary measure. Egg freezing is intended to preserve a woman’s fertility, since it is able to put the biological clock on hold. This means the woman can use her own cryopreserved oocytes to get pregnant at a later point in time.

1. In what situations would egg freezing be useful for women?
2. Treatment process
3. Safe freezing technique

1. In what situations would egg freezing be useful for women?

Egg freezing is a sensible precautionary step in cases where specific medical circumstances are deemed to have a detrimental effect on a woman’s oocytes, e.g. an upcoming radio- or chemotherapy, or in women who - in view of the ongoing changes in our society and lifestyle - want to delay motherhood. As a consequence of the latter, today, women are making the decision to have children later in life: after completion of their professional or academic training, when their financial situation has become stable etc. Very often, this objective is not achieved until the woman is in her mid-thirties. For this reason, and in view of the biological fact that a woman's eggs are subject to an ageing process and that it is, for instance, increasingly difficult for women to become pregnant after the age of 38, we strongly encourage women to freeze their eggs while they are young (between the ages of 20 and 35) as a precautionary measure. The aim is to counteract problems related to an age-related decline in female fertiliy. The legal regulations for egg cell preservation vary from country to country (see also "Note Austria").

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The precautionary freezing of egg cells

2. Treatment process

The treatment starts with an extensive consulting interview, comprehensive information, also as regards potential risks and complications. A gynecological examination, hormonal and serologic testing (infection parameters) do also play a crucial role when it comes to fertility preservation. During the preparation phase, the ovaries are stimulated by means of a targeted hormone treatment (IMPORTANT: Reliable contraception to prevent an unplanned pregnancy is crucial from the start of the stimulation phase up to the next menstrual period). Follicle growth is closely monitored by ultrasound examinations in order to determine the optimum time for egg collection. After follicular puncture, the retrieved eggs are frozen and stored.

3. Safe freezing technique

Aseptic vitrification is a modern and innovative freezing technique (learn more), which allows the cryopreservation of unfertilized oocytes without compromising their developmental potential. The efficient and, above all, safe application of aseptic vitrification is an integral part of the daily work in our IVF centers. Aseptic vitrification is a science-backed procedure. The oocytes are frozen inside a protective cryo-straw at -196°, which is then stored in a tank filled with nitrogen.


In Austria, preventive freezing of egg cells requires a medical indication. The freezing of eggs without such a medical indication is prohibited in Austria. Such threatments are therefore not carried out in Austria.

For further information, we would be pleased to offer you a personal consultation.