With the reception of oocytes, the female sex cell (oocyte) is provided by a different woman, willing to donate egg to which she will become pregnant. The choice of the donor is made on the basis of the physical and analytical characteristics of the receiving, and the affiliation of both will remain anonymous as specifically provided for in the Assisted Reproduction Act.

The donated oocytes are fertilized by sperm microinjection (ICSI) with the sperm of the patient partner or with donor sperm. The embryos obtained will be transferred to the patient (a maximum of three).

Egg donation does not affect the future fertility of the donor or advance the age of menopause, does not raise the risk of gynaecological cancer and does not produce weight gain.

This treatment is recomended to womens who have undergone surgery and have no ovaries, or who do not function because they have reached the menopausal state or received very aggressive treatments at the cellular level such as radio or chemotherapy.

It is also an alternative when the woman is at risk of transmitting to the offspring some type of hereditary disease or when other assisted reproductive treatments where own oocytes have been used, have failed.