Experts have raised a warning over a new procedure which claims to delay the menopause.
The method - created by Birmingham-based company ProFam - claims to delay the menopause by over a decade by removing and freezing a small fraction of healthy ovarian tissue and saving it for later life.
The menopause is brought on by falling levels of the hormone oestrogen, which produced in the ovaries.
This new procedure involves removing a “healthy” piece of ovarian tissue from a younger woman and freezing it - so when the woman reaches change in later life, the tissue can be thawed and grafted into the body - therefore reintroducing the oestrogen.
BBC reports that 11 women have had the operation so far - with some paying £6,000 for the procedure.
Prof Fishel - the leading IVF expert atProFam - believes the procedure to be beneficial, as it introduces more eggs and the ovary is more "hormone-packed".
But experts are raising concerns surrounding the long-term safety of the method and the fact that success with it remains untested.
Dr Melanie Davies, who chairs Fertility Preservation UK, warns against "healthy women going through surgery that would not otherwise be needed... in the hope of preserving future fertility and hormone replacement.”
She adds, "We know that fertility can be restored in a proportion of women that have had cancer.
"But no healthy women have gone through this yet and there is no evidence that graft will last more than 10 years.
"So it will be of limited help for hormone replacement."
Dr Davies - who also sits on the British Menopause Society's Medical Advisory Committee - instead urges women to consider “well researched and widely available” hormone replacement therapy (HRT).
For those looking to have a baby in later life, Dr Davies suggests egg freezing as a "far better established procedure" than Prof Fishel's "unproven technique".
Dr Davies also says the potential impact of removing ovarian tissue on long-term ovarian function, including fertility, needs "further assessment and evaluation”.