Success rates

You have the best chances of giving birth to a healthy baby using donor eggs from a healthy young woman and having 1 to a maximum of 2 embryos (selected blastocysts) transferred to your uterus. Although the implantation of the embryo can be supported by medication, there are no means to force this process.

Please be aware that we cannot give any guarantee for a successful treatment outcome.

We usually perform the egg donation procedure in a subsequent cryopreservation cycle. This means that the ova collected from the donor is fertilized by the sperm of the recipient’s male partner. If there is a sufficient number of fertilized egg cells offering a great chance to achieve pregnancy, these eggs will be cryopreserved and stored until the endometrium of your uterus is optimally prepared for embryo implantation and a successful pregnancy outcome. Cryopreservation does not have a negative impact neither on the embryo nor on the pregnancy rates!

Why do we choose this particular procedure?

The egg donor is undergoing ovarian stimulation while, at the same time, your uterus is being prepared for embryo implantation by hormonal treatment. This might lead to situations that are neither beneficial nor agreeable to you or the donor:

• In some cases the donor’s organism hormonally interferes with the maturation process of the egg cells, so  that the therapy cycle has to be interrupted.

• In very rare cases, it might also occur that no egg cells can be obtained during follicular puncture.

• Neither can we influence the process of fertilization. Thus it may happen, that fusion of egg and sperm does not occur.

• Synchronization problems between donor and recipient: There is repeated occurrence of cases where the  recipient’s endometrium has not yet reached the optimum thickness on the day scheduled for a “fresh”  embryo transfer (some women need more time to reach the required endometrial thickness, in other women  it may be recommended to increase the dosage of hormones). Transfer within the so-called  cryopreservation-cycle can be postponed until the endometrium has reached the optimum thickness. The  embryos are not thawed until the date for embryo transfer is definitely fixed.

General information about the chances of pregnancy following “classic” in vitro fertilization

The chances of success of an IVF/ICSI/IMSI treatment need to be assessed individually. By taking into account all patients presenting a normal hormonal balance and normal sperm quality who are treated at experienced IVF centers using conventional culture techniques (d2 or d3 after oocyte pick-up), success rates between 25 %-37 % per egg collection may be achieved.

Taking account of specific criteria (age of the woman, hormonal disorders, endometriosis, medical indication of treatment and prolonged culture up to the blastocyst stage etc.), entirely different results are to be expected. A woman under the age of 35 with a good response to ovarian stimulation (more than 10 egg cells obtained per egg retrieval) and the embryos to be transferred at the blastocyst stage has the best chances of a successful pregnancy (up to 80 % of these cases may result in a positive pregnancy test).

The situation becomes more difficult with increasing age of the woman. Beyond the age of 40 – in spite of optimum preparation and good response to ovarian stimulation – the chances of getting pregnant are reduced. From the age of 44 onwards the pregnancy rate drops to 5 % and less!

Please note:

The more difficult the initial situation, the more important is the application of promising technologies at our disposal in order to be successful (blastocyst selection, IMSI, ISME-T, etc.).

Egg donors are thoroughly screened and carefully chosen. They are young and healthy, thus enabling high chances for success.


IVF Centers Prof. Zech
Tel.: +43 5574 44836
Tel.: +43 662 9010 5000
Tel.: +41 71 950 1580
Tel.: +423 237 6655
Czech Republic
Tel.: +42 0377 279 350
Tel.: +39 0473 270470

providing scientific and technical
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The Bridge Clinics
Lagos State, Nigeria
Tel.: +234 1 461 9006