Choosing the right Egg Donor: What you need to know

Laura Garcia de Miguel, MD
Fertility Specialist & Medical Director, Clinica Tambre

Donor Eggs

From this video you will find out:
  • What does the egg donation process look like, and how does it work in Spain?
  • What are the criteria for selecting an egg donor in Spain?
  • What are the indications for egg donation treatment?
  • How are the donors matched with the recipient?
  • How does immunological matching, specifically the KIR-HLA-C interaction, influence the success of egg donation procedures, and what are its implications for recipients and donors?

Choosing the right Egg Donor: What you need to know

Dr Laura García de Miguel, Medical Director at Clínica Tambre the process of choosing the right egg donor. Dr García explained the importance of medical screening for potential egg donors, what information about the donor’s history is provided and how are they matched with the recipients.

Understanding the importance of egg donation

As we all know, egg donors are essential when a woman or couple is recommended to undergo egg donation or double donation. During this webinar, Dr Laura García de Miguel focused on egg donation. Instead of using eggs from a patient who will become pregnant in the future, we use eggs from a donor. The selection and matching of egg donors depend on various factors, particularly the country, legal aspects, cultural differences, and the specific protocols of each clinic, even within the same country.

Egg donation in Spain – legal and ethical considerations

Spanish legislation mandates that egg donation must involve anonymous, voluntary, and altruistic donors. Donors must undergo a rigorous selection process, including medical and psychological evaluations, to ensure eligibility and minimize genetic and other risks. All Spanish fertility clinics report donor data to a system called SIRHA, which limits donations to individuals whose gametes have already contributed to the birth of six babies. This ensures proper regulation and control.

The egg donation process at Clínica Tambre: a step-by-step journey

How is the egg donation treatment process performed at Clínica Tambre? There are several indications for undergoing egg donation treatment, such as premature ovarian failure, menopause, previous IVF failures, low egg quantity or quality, hereditary issues, or certain medical conditions like chemotherapy or endometriosis.

The treatment at Clínica Tambre involves a series of steps, including confirming the treatment, collecting essential medical data, undergoing ultrasounds, and preparing the uterine lining. The egg collection, fertilization with sperm, and embryo transfer follow this. The recipient continues with estrogen and progesterone medications, and a pregnancy test is done at home, followed by scans during the pregnancy.

Selecting the ideal egg donor

What is involved in egg donor selection at Clínica Tambre? The selection criteria include women under 35 (preferably under 32) with specific height (1.55 m) and body mass index (max 30) requirements. Medical evaluations, psychological tests, and genetic tests are conducted. The donor’s race and ethnicity are considered, as the clinic has experience with various phenotypes. The selection also factors in immunological matching when needed.

The physical selection of donors takes into account their characteristics, blood type, and the patient’s preferences. This selection is always done by the clinic to ensure anonymity.

Fenomatch technology is utilized to assess genetic similarities, using biometric facial techniques. The best donor match is determined by physical characteristics, questionnaire responses, photos, and blood type compatibility. Immunological matching is considered for patients with a history of failures or miscarriages, while genetic matching can reduce the risk of inherited diseases.

Immunological matching (KIR-HLA-C)

What is the immunological matching KIR HLA-C combination? In patients with a history of previous failures and a long track record of unsuccessful embryos, we explore the compatibility between uterine KIR lymphocytes and HLA-C molecules presented by the embryos. This means that in cases where patients have a history of both failures and miscarriages, we conduct a blood test to assess the KIR receptor in the lymphocytes. This test, which is not widely available in many countries, is easily administered at Tambre. If the KIR receptor is aggressive, signified by KIR AA, we require specific donor selection in the immunological system, specifically involving HLA-C1C1 of the donor. This approach helps prevent an aggressive immune reaction.

Genetic matching

Genetic matching is another essential aspect of discussion when considering egg donation. This involves a blood test that assesses the status of more than 300 recessive genetic diseases for the recipient. It’s important to note that every person can carry one or more recessive mutations, and this is not inherently problematic. However, if we were to fertilize an egg from a recipient who shares the same recessive mutation as the donor, there would be a potential risk of the baby being born with a genetic disease. Consequently, when patients express interest in genetic matching, we need to ensure compatibility through our laboratory and genetic testing to eliminate any risk. It’s crucial to emphasize that the likelihood of this scenario is exceedingly rare, with less than 1 in every 1,000 babies being affected each year.


In conclusion, there are no ‘good’ or ‘bad’ donors, but rather compatible ones. Compatibility extends beyond physical characteristics to include blood type, immunological matching, and genetic compatibility if desired. It’s vital for patients to have comprehensive information about the donor screening process at their chosen clinic to make an informed decision.

- Questions and Answers

How many donor embryos are usually needed for one live birth?

With our success rates, we have around a 65-70% probability of implantation with one embryo transfer. However, this can vary among patients. After 3 unsuccessful embryo transfers, we start considering recurrent implantation failure and investigate further.

My donor had a very poor blastulation rate, only 3 out of 7 embryos got to the blastocyst stage. Do you recommend PGT-A? What are the chances the baby could inherit a genetic disease?

Three out of seven embryos reaching the blastocyst stage is slightly below the expected ratio, but not necessarily a concern. We generally don’t recommend PGT-A for already-created embryos because it’s an invasive procedure. The risk of inheriting a genetic disease from a donor with no known genetic issues is very low, less than 1 in 1,000.

Do you offer counseling and support services for both intended parents and egg donors at Tambre? Are there any cases where counseling played a significant role?

Yes, we offer psychological and medical counseling as needed for both intended parents and egg donors. Counseling can play a significant role, especially when addressing specific issues or concerns related to the family’s health history.

If someone suffers from implantation failures, would you not investigate this first before using donor eggs?

Definitely, we recommend investigating implantation failures to determine whether using donor eggs is necessary. It’s important to identify the root cause before moving on to egg donation.

What is the age limit for egg donors in Spain?

The maximum age for egg donors in Spain is 35, but we recommend donors between 18 and 32 years old.

Where do the egg donors mostly come from? Are there specific criteria for donors?

Egg donors primarily come from Madrid, but we may work with people from other regions temporarily. We focus on those living in Madrid because of the need for multiple tests and the donation process.

What is the maximum age limit for recipients in Spain?

There’s no legal restriction for recipients in Spain, but it’s recommended not to do embryo transfers for recipients over 50 years old.

Do you complete the embryo transfers in the morning or afternoon at your clinic?

We typically complete embryo transfers around midday at our clinic (Clinica Tambre).
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Laura Garcia de Miguel, MD

Laura Garcia de Miguel, MD

Dr Laura García de Miguel has worked in the field of gynaecology and obstetrics since 2008. At present, she is a medical director of Clínica Tambre in Madrid, Spain. Dr García de Miguel has extensive experience in IVF and provides a highly personalized approach to each and every patient and custom-tailored treatments to meet the needs of various patients. Dr García de Miguel specializes in treating patients who have had previous IVF failures or who respond poorly to hormonal or IVF treatment. Dr Laura speaks fluent Spanish, English, and French and treats patients from all over the world.
Event Moderator
Caroline Kulczycka

Caroline Kulczycka

Caroline Kulczycka is managing MyIVFAnswers.com and has been hosting IVFWEBINARS dedicated to patients struggling with infertility since 2020. She's highly motivated and believes that educating patients so that they can make informed decisions is essential in their IVF journey. In the past, she has been working as an International Patient Coordinator, where she was helping and directing patients on their right path. She also worked in the tourism industry, and dealt with international customers on a daily basis, including working abroad. In her free time, you’ll find her travelling, biking, learning new things, or spending time outdoors.