What are these?
Egg donation is the donation of eggs by one woman for use in IVF treatment by another woman. The sperm from the male partner of the receiving woman is used to fertilise the donated eggs.
Embryo donation is the donation of fertilised eggs by one couple for use in the treatment of another. In this case the eggs have already been fertilised by sperm from the donating male partner. Both are regulated by the Human Fertilisation and Embryology Authority (HFEA) in the UK and strictly monitored.
Who can donate eggs and embryos?
Any healthy woman (or couple) that is free of genetic or transmittable diseases can potentially be an egg (or embryo) donor. Potential donors undergo a screening process that includes a detailed history and examination. Investigations include blood tests to check for chromosomes and infections like HIV, hepatitis, syphilis and cytomegalovirus, and vaginal swabs for sexually transmitted diseases like gonorrhoea and chlamydia. Embryo donors are usually couples who have undergone full IVF treatment and still have frozen embryos for which they have no further use.
Who needs donated eggs?
Some women cannot produce their own eggs because they have undergone the menopause prematurely and will need donated eggs or embryos to be able to have children. This inability to produce eggs may also be due to problems the woman is born with or could develop later in life because of infection, medical treatment or surgery. Likewise, women with abnormal eggs and those with a genetic abnormality that they do not wish to pass on to their children will need donated eggs or embryos.
How are they performed?
Egg or embryo donors as well as the receiving couple will need to undergo detailed assessment and counselling before undergoing treatment. Egg and embryo recipients may know who their donors are (known donation) or may wish to use anonymously donated eggs/embryos.
Egg donors will need to undergo controlled stimulation of the ovaries and collection of the eggs (see ‘in vitro fertilisation’). The receiving male partner will be requested to produce a sperm sample by masturbation on the day the donor’s eggs are collected. The eggs and sperm are mixed together (or if necessary a single sperm is injected into each egg in a procedure called intracytoplasmic sperm injection) and left overnight. By the next morning it is clear how many eggs have been fertilised by the sperm to become embryos.
Couples having known egg donation may be able to have the fertilised eggs replaced fresh (two days after the egg recovery). Following anonymous egg donation, the fertilised eggs may be replaced fresh (immediately) or frozen for six months to quarantine them against transmissible infections in the donor. This time allows for further blood tests in the donor to ensure absence of these infections.
The embryos (whether fresh or frozen) may be replaced in natural or hormone prepared cycles. Natural cycles are suitable for women with normal regular ovulation while others will need preparation of the womb using hormone tablets, pessaries (vaginal tablets) and injections. Artificial hormones that have been used to prepare the womb will need to be continued for some time after the replacement, often up to the 12th week of any resulting pregnancy. Details of replacement procedures, number of embryos replaced, and what happens afterwards can be found in the section on ‘in vitro fertilisation’.
Donated embryos are usually frozen and may be replaced in natural or hormone prepared cycles (as above). The procedures are similar to those for replacement of fertilised donated eggs detailed above.
How successful are they?
Couples have a greater chance of becoming pregnant and having children following treatment with donated eggs or embryos than with conventional IVF or ICSI. This is because young (less than 35 years old) healthy women with proven fertility usually donate the eggs or embryos. The average chance of a couple in the UK achieving a child from each cycle of treatment using donated eggs or embryos is about 1 in 5. The HFEA publishes a yearly guide to UK clinics that offer treatment with donated eggs or embryos and interested couples may obtain a copy of this by telephoning 0207 377 5077.
There are implications that all involved parties need to be aware of:
- Payment of donors – this is a contentious issue and the legislation concerning it varies from country to country. The family doctor, gynaecologist or infertility specialist will usually be able to advise couples of the current legislation governing this form of treatment in their different localities. The current legislation in the UK holds that egg and embryo (indeed any body tissue) donation should be performed altruistically and not attract any form of payment, except where this is to cover reasonable expenses incurred by the donor in the process of the donation.
- Egg sharing – some units in the UK practise this. It refers to treatment of two couples using eggs obtained from the female member of only one of the couples. Typically, one couple bears the financial burden of the treatment while the other female undergoes controlled stimulation of the ovaries and egg collection. The collected eggs are shared out between the two couples following a pre-agreed pattern and then used for IVF or ICSI treatment. This practice may make treatment possible for couples that otherwise may not be able to undertake it themselves but has a potential for abuse. Couples contemplating egg sharing will need to discuss the issues thoroughly beforehand and agree a plan of action especially with regard to how the eggs are shared and any future problems coped with. These will include success in one but not the other couple.
- Anonymity – the regulations governing this again vary according to country. Legislation in the UK has recently changed to give offspring of egg or embryo donation cycles the right to find out the identity of their genetic parents once they reach their eighteenth birthday.
- Legal parents – the legislation governing this may again vary from country to country and couples need to seek guidance from their healthcare providers about local regulations. Current legislation in the UK holds that the man and woman receiving the treatment are the legal parents of any child that results. For unmarried couples, the man is not automatically awarded legal parent status and has to apply for this through the courts, as does any man who has a child outside wedlock.
- Informing the child – there is no legal requirement for couples that have been successful with this treatment to inform the children of their origin. However, most clinics now recognize that children have rights to know about their conception. Some units arrange some sort of yearly reunion for children born from this and other forms of assisted conception treatment (including DI, IVF and ICSI) to reinforce the normality of such children. Counselling is available at all licensed clinics to discuss the implications of using donated eggs and embryos.