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.
- Removal of ovaries because of cancerous growth or severe Endometriosis.
- Chemotherapy or radiotherapy for cancer. This often stops the ovaries working properly.
- The ovaries are in decline and produce poor quality eggs, usually in women over the age of 40.
All the above problems lead to donor eggs as the recommended most viable option. The egg donor herself may be anonymous or may even be a close friend. Due to the lack of egg donors close matching of characteristics is not always possible. As with others forms of tissue donation, donors must be screened for the HIV virus (AIDS) and hepatitis viruses. Careful counselling of all the individuals involved in treatment is essential.
The treatment involves:
- Production of eggs by the donor using the usual drugs for IVF.
- Fertilisation of the eggs with sperm from the patient’s partner.
- The transfer of two (or in exceptional circumstances three) of the resulting embryos into the patient’s womb.
The baby is therefore the genetic child of the male partner and the egg donor but any pregnancy is carried by the patient. The child also legally belongs to the patient.
The procedure is therefore 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.
The embryos produced during treatment can be transferred in two possible ways:
a) Fresh Embryo Replacement
This involves drug treatment of the donor and the patient so that their menstrual cycles become synchronised. The patient who needs this kind of treatment will usually 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 patient’s womb on day 2, 3, 5 or 6.
b) Frozen Embryo Replacement
Once the donor eggs have been fertilised the resulting embryos are frozen in liquid nitrogen and stored until the 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).
The 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.