Egg donation success rates: figures from the registers, and how to interpret them

This is often the first question asked, even before the question of cost: ‘What are my chances?’ With egg donation, the outcome is better than with one’s own eggs after the age of 40, and much less dependent on age. But it varies depending on what is being measured, and this is where the figures quoted can be misleading. Here are the figures from the major registers, which are independent of any specific clinic.

What the registries say

These figures do not contradict each other: they do not measure the same thing. A pregnancy is not a birth, a transfer is not a cycle, and a transferred embryo is not a patient.

Four ways of counting

• Per transfer: the most favourable figure, as it only counts cycles that have progressed to the transfer stage.
• Pregnancy or birth: between the two, there are miscarriages. A ‘pregnancy’ rate, especially if it is based solely on a positive test, is always higher than a birth rate.
• Per transferred embryo: this is the measure used by the UK authorities, which allows for a comparison between practices involving the transfer of one or two embryos.
• Cumulative: the chance of having a child using all the embryos from a single donation, both fresh and frozen. This is the figure that matters most to you, and the one least often published.

How to interpret any success rate is explained in detail in the article on success rates.

Fresh or vitrified eggs

The European registry shows a slight advantage for fresh eggs: 51.3 per cent pregnancy per transfer compared with 45.7 per cent with thawed eggs in 2020; the US registry for 2022 shows almost no difference, with 39.2 per cent versus 38.9 per cent births. The benchmark randomised trial, conducted in a highly experienced laboratory, found no difference, however. The discrepancy therefore depends mainly on the laboratory and the number of eggs allocated; further details can be found in the article on fresh versus vitrified eggs.

The recipient’s age matters little

Data from the UK clearly demonstrate this: with egg donation, the birth rate per transferred embryo remained above 30 per cent across all age groups in 2019, including among women aged between 45 and 50. This makes sense, as embryo quality depends on the donor’s age, and in Greece an egg donor must be under 35, unless an exception is authorised by the National Authority for Assisted Reproduction. What does not diminish with age are the risks associated with pregnancy itself: see pregnancy after the age of 40 and the risks of pregnancy following IVF.

Factors affecting your chances

• Embryos: their number and quality, which depend on the eggs received, the sperm and the laboratory. See how many eggs are needed for one embryo.
• The uterus: a polyp, a fibroid that distorts the cavity or a thin endometrium can reduce the chances of success and are often treated before the transfer.
• The partner’s sperm, when used.
• Weight, smoking, and general health.
• The number of embryos transferred: in Greece, for egg donation, the National Authority’s regulations limit the transfer to a maximum of two embryos, regardless of age. Transferring a single embryo at a time significantly reduces the risk of a twin pregnancy; see one embryo or two.

Why Greek clinics do not publish their success rates

You will often search in vain for a success rate on a Greek clinic’s website. This is not a lack of transparency: the National Authority for Assisted Reproduction’s code of practice prohibits clinics from publishing their success rates, the number of cycles they carry out, or any comparisons with other clinics. A very high figure displayed by an intermediary, or presented without explaining what it measures, therefore warrants even greater caution. During a consultation, however, you can ask the doctor what they have observed in patients in your situation, and exactly what their figure measures.

If you would like us to look together at the validity of the figures you have been given, please write to me.

Frequently asked questions

Source: https://fertilitegrece.com/en/blog/egg-donation-success-rates/ — Triada Baloukoudis, IVF patient coordination in Greece. General information, not medical or legal advice. Printed on

Triada Baloukoudis
Independent IVF patient coordinator in Thessaloniki, with 24 years of experience supporting patients travelling from abroad. More · Contact · Facebook