A TEST developed in Sheffield to predict how long a woman will remain fertile will be available in January.
The kit has been developed by Professor Bill Ledger of Sheffield University to tell women how much fertile time they have left to start a family.
It works by measuring levels of three hormones in the blood and assessing when the menopause is imminen
t and could help thousands of women to plan their families. A cost for the test has yet to be decided.
According to the Human Fertilisation and Embryology Authority, a woman is half as fertile at 35 as she is at 25, and half as fertile again at 40.
On average, a woman will go through the menopause aged around 50, but it can happen as early as 42 and as late as 58.
Professor Ledger, who also works at the Jessop Wing, said pilot studies had been a success and that several women had changed their plans and decided to try for a baby earlier based on test results.
But the test would not alter the fact that a women's eggs decline in quality with age, increasing the risk of conditions such as Down's syndrome. Older mothers are also at greater risk of complications such as miscarriage.
The test, which will be available at pharmacies and possibly by mail order, measures the levels of three hormones. Two, produced by the ovaries, go down as the menopause nears, while the other, released by the brain, increases.
By analysing the different levels over time it should be possible to plot how close to the menopause a woman is.
Other factors, such as their partner's health, are also important in determining fertility.
Clare Brown, chief executive of Infertility Network UK said: "This is obviously a good method of giving a women an indication of their current fertility in terms of how many viable eggs they have left.
"It is important to recognise however, that ovarian reserve is not the only aspect of a woman's fertility which may have an effect on whether or not she is able to conceive.
"Indeed there are many other factors which can affect conception. While recognising this is a valuable test, we would urge caution in taking any one single factor as an indication of present or future fertility."
