Ovarian tissue
Ovaries and ovarian tissue
Ovaries are part of the female reproductive system. When a girl is born she will usually have two ovaries in her pelvis.
The ovaries at birth contain her full complement of immature eggs (between one and three million immature eggs). These immature eggs are found in the outer part of the ovary called the 'ovarian cortex'.
On a daily basis from birth up to the time of the menopause (usually about 50 years of age) groups of the immature eggs start to develop.
After puberty, it is the developing eggs that produce oestrogen and lead to the monthly cycle.
The cortex of the ovary, containing all the immature eggs, can be cryopreserved and stored for future use.
Collection and storage
We usually collect ovarian tissue during a short keyhole operation under general anaesthetic, which we arrange before treatment starts if possible.
During the operation, the surgeon routinely removes one ovary (oophorectomy) or small pieces called 'biopsies'. This tissue (ovary or biopsies) is transported immediately to the Oxford Cell and Tissue Biobank (OCTB) in Oxford.
There we carefully preserve the tissue and freeze it using a specialised cryopreservation process. We then safely store the tissue at ultra-low temperatures (around -170°C).
Future use
Cryopreserved ovarian tissue containing the immature eggs can be thawed and immediately re-implanted back into or near the patient's ovary.
After a few months this usually leads to the restoration of normal ovarian function, monthly cycles and egg development.
In future there may be a wider range of techniques established, increasing the options available. We can discuss these with you when you wish to pursue a pregnancy.
Success rates
Ovarian tissue cryopreservation programmes have been running in a number of centres around the world for over 20 years.
The available, published data on successful pregnancies after using this technology is very encouraging. Over 95 percent of patients have restored hormonal production within six months of re-implantation.
There have also been a significant number of births recorded.
Success rates are similar to other methods of fertility preservation (e.g. egg freezing).
As with all methods of fertility preservation, use of cryopreserved ovarian tissue cannot guarantee the chance of a successful pregnancy in the future.
