This technique is recommended when the sterility factor is caused by problems derived from the patient's low quantity and/or poor quality of eggs. This can be caused by different reasons:

• Congenital or acquired absence of ovaries
• Early menopause
• Chromosomal abnormalities that are transmitted to offspring
• Lack of ovarian stimulation
• Repeated IVF failure
• Recurrent miscarriages

In Spain, the Law states that donation is anonymous, altruistic and voluntary.

Donors are healthy women, between 18 and 35 years old, who want to help other women become mothers. All candidates must have good psychophysical health and full legal capacity.

Different studies are carried out to demonstrate that they do not suffer from genetic, hereditary or infectious diseases that could be transmitted to offspring. As recommended by the Spanish Fertility Society, one of them is the Basic Genetic Screening that determines whether the donor is a carrier of pathogenic variants such as: Cystic Fibrosis (CFTR), Spinal Muscular Atrophy (SMA), Non-Syndromic Neurosensory Deafness (GJB2), most prevalent Hemoglobinopathies and Fragile X.

Additionally, Expanded Genetic Screening (Carrier Test) can also be performed to identify a greater number of pathogenic variants, to prevent these from being shared with the recipient patient's partner (matching). The Expanded Genetic Screening also includes the study of all variants included in the Basic screening.

The eggs obtained from the donor are inseminated with the semen of the recipient patient's partner to obtain the embryos, which will be transferred to the recipient's uterus.

Prior to this transfer, the patient receives mild hormonal treatment to prepare the uterus and facilitate implantation.