Egg donation (oocyte donation)
This treatment is recommended for women who cannot produce their own eggs. There are several reasons why a woman may find herself in this scenario. The most common are:
- The ovaries are no longer working properly because of the premature onset of menopause.
- The ovaries are in decline and produce poor quality eggs, usually in women over the age of 40
- Previous chemotherapy or radiotherapy for cancer. This often stops the ovaries working properly.
- Previous removal of ovaries.
- Severe endometriosis
Any of the above problems may lead to treatment with donor eggs being the recommended option. The egg donor herself can be anonymous or may even be a close relative or friend. Due to the lack of egg donors, close matching of characteristics is not always possible.
As with other forms of tissue donation, donors must be screened for the HIV virus (AIDS), hepatitis viruses and all known sexually transmitted diseases. Careful counselling of all the individuals involved in treatment is essential.
The treatment involves:
- Production of eggs in the donor using the usual drugs for IVF.
- Fertilisation of the eggs with sperm from the patient’s partner.
- The transfer of one or two (or in exceptional circumstances three) of the resulting embryos into the patient’s womb.
The procedure is very similar to standard In-Vitro Fertilisation (IVF) but the egg donor rather than the patient receives the drugs to stimulate egg production. More information about IVF can be found on the In-Vitro Fertilisation pages.
If treatment is successful, the baby will be the genetic child of the male partner and the egg donor but the pregnancy is carried by the patient. The child legally belongs to the patient, not the egg donor.
The embryos produced during treatment can be transferred in two possible ways:
- a) Fresh Embryo Transfer
This involves drug treatment of the egg donor and the recipient patient so that their menstrual cycles become synchronised. The recipient patient who needs this kind of treatment will be taking hormone replacement therapy (HRT) to build up the lining of the womb.
Following the egg collection, one to two embryos are replaced in the recipient patient’s womb on day 2, 3, 5 or 6.
- b) Frozen Embryo Transfer
The remaining embryos created from donated eggs following a fresh cycle can be stored for future use. These embryos are frozen in liquid nitrogen and stored until the recipient patient is ready for transfer. Embryos can either be stored at 2-pronuclear stage (soon after fertilisation) or cleavage stage (after splitting into 2 or more cells).
In preparation for the transfer the recipient patient takes oestrogen hormones to develop the lining of the womb. Embryos are thawed, examined to make sure they have survived and are developing as expected before being placed in the womb. Embryos frozen at 2-pronuclear stage are thawed out 24 hours prior to the frozen embryo transfer. Cleavage stage embryos are thawed on the same day as transfer.