What is In Vitro Fertilization with Donor Egg and when Should be Done?

1. Donor selection

Donors are selected based on an extremely strict medical criteria test and undergo a series of tests to rule out any major diseases and conditions that may have repercussions on the baby’s health.

One of the distinctive features of our donation programme is that we attempt to match the physical characteristics (phenotypes) of the donor and the recipient as closely as possible. This is what we call good phenotype matching. The results are closely examined by a doctor, who also checks for the absence of currently known genetic diseases in the donor’s personal or family history, and a psychologist who assesses the donor’s mental health.

Finally, the donor signs a consent form drawn up according to Spanish law, in which she states that she is donating her eggs to a couple wanting a child and that she will never try to find out who they are.

2. Donor treatment

Donors have to undergo a course of treatment for about two weeks to stimulate their ovaries; this consists of administering subcutaneous (under the skin) hormone injections and they are monitored with ultrasound scans plus blood tests if necessary. The eggs are removed by inserting a fine needle into the ovary while the woman is under sedation.

3. Obtaining the semen sample

The semen sample is obtained from a donor who has undergone a full medical check (semen analysis, blood and urine tests, general examination, tests for sexually transmitted diseases and psychological examination) to ensure the quality of their sperm and rule out any kind of abnormality. All donors are adults and sign a consent form that also guarantees their anonymity. The semen is frozen before being used.

4. Egg harvesting and In Vitro Fertilisation

Harvesting the eggs is done by inserting a needle into an ovarian follicle and aspirating them. Once they have been harvested, the eggs are placed in a culture dish for a few hours while the semen is being prepared to separate motile sperm.

If the technique that will be used is ICSI (injecting a sperm into each mature egg) the eggs are denuded, which means that the cells on the surface are removed, and a sperm is injected into each one. At our Clinic, we carry out ICSI in 99% of cases, unless requested not to do so.

If not, the sperm (between 50,000 and 100,000) are placed in the culture dish with the eggs and the next day they are checked to see how many have been fertilised. Obviously, the more eggs we have the greater chance there is of obtaining a pregnancy.

5. Transfer

The day after harvesting and the ICSI procedure we will know how many eggs have been fertilised. Over the next 2 or 3 days, these fertilised eggs become pre-embryos ready to be transferred to the uterus.

On day of transfer, the pre-embryos showing the best signs of developing are selected. The law permits us to transfer up to 3 pre-embryos, but the average number is 2.

The pre-embryos are placed in a thin catheter and the gynaecologist inserts the eggs deep inside the uterus. No anaesthetic is required for this procedure. Of the transferred pre-embryos, normally only one will implant, but bear in mind that sometimes more than one may implant, resulting in a multiple pregnancy.

6. Cryopreservation

The pre-embryos that have not been transferred are frozen in liquid nitrogen (this type of cryopreservation is known as Vitrification) and they are then carefully labelled and stored in the embryo bank. These pre-embryos can be used in subsequent cycles if a pregnancy is not achieved on the first attempt. Evidently, the treatment for preparing the uterus for the transfer of frozen embryos is much simpler as there is no need to stimulate the follicles and harvest the eggs.

Who Are Appropriate Candidates For Donor Egg?

The primary indication for egg donation was originally for women with premature ovarian failure (POF), defined as menopause occurring before the age of 40 years. POF affects approximately 1% of the female population; in effect, this condition indicates depletion of a woman’s own eggs and cessation of ovarian function. The causes of POF are varied, and a thorough medical evaluation to seek an underlying or associated process is important prior to treatment.

In recent years, the predominant indication for egg donation at most IVF centers has been for women with diminished ovarian reserve but with intact ovarian function. It has long been known that women over 40 years old have reduced fertility in general, and a poorer chance for success after IVF. This gradual, age-related decline in fertility is a direct result of aging of the eggs. The fertility evaluation may also uncover evidence of diminished ovarian reserve even in women younger than 40 years, as reflected by elevated FSH (follicle-stimulating hormone) and/or estradiol levels early in the menstrual cycle, determined by a blood sample taken on cycle day 2 or 3.

Other potential candidates for egg donation include: women who have previously failed multiple IVF attempts, particularly when poor egg quality is suspected, and women carrying transmittable genetic abnormalities which could affect their offspring (this latter indication has declined with the development and use of pre-implantation genetic diagnosis, or PGD).