Test predicts when menopause will begin

Women will be able to learn how late they can put off having a family by using a test that can predict the length of their reproductive life.

Women will be able to learn how late they can put off having a family by using a test that can predict the length of their reproductive life.

The test can reveal in advance the timing of the woman's menopause, allowing her to plan her career and family to fit in with her biological clock, researchers said.

The discovery has significant social and medical implications for women anxious to know how long they can put off motherhood without leaving it too late.

Initially, however, it is likely to be of greatest use to women whose long-term fertility has been affected by diseases such as cancer or genetic factors.

Hamish Wallace, a consultant at the Royal Hospital for Sick Children in Edinburgh, who led the research, said: "In essence, it means we now have the potential to be able to tell a woman how fast her biological clock is ticking and how much time she has before it will run down."

The test is conducted using an ultrasound probe inserted through the vagina to measure the size of the ovaries. Each woman is born with a fixed pool of immature eggs which are released each month from puberty. By the age of 37 there are on average only 25,000 eggs left and the decline accelerates. When the supply is down to 1,000 - too few to generate a mature egg capable of being fertilised - the menopause begins marking the end of the woman's reproductive life.

Normally the menopause occurs about the age of 50 but it can start at any time from the early forties to the late fifties.

Studies have already shown that a woman's ovaries shrink as they age and this is linked to the declining number of immature eggs that they contain. By measuring the size of a woman's ovaries and comparing them with what would be expected for a woman of her age, researchers were able to predict when the menopause would occur.

In examinations of two women aged 40, they calculated that one with larger ovaries would experience the menopause at age 54 or 55, while one with smaller ovaries would reach the menopause at the age of 48 or 49. The calculations involve complex mathematical modelling carried out by a computer expert at the University of St Andrews, Thomas Kelsey.

The researchers, whose study is published in Human Reproduction, developed their technique while researching the likely menopause age of young women who have had cancer.

Radiotherapy applied to any part of the body can kill ovarian cells and impair fertility, bringing about an early menopause. The scientists wanted to find a way of letting these women know how much time they had left in which to plan a family.

Having developed the test, they realised it could also be used to work out the reproductive lifespans of healthy women.

Dr Kelsey said: "Ultrasound is an ideal method, because it is safe, non-destructive and relatively cheap. The technology already exists and is readily available all over the Western world. It is possible this service can be made available at GP surgeries or at fertility clinics, and would be a likely first step in the family planning scenario."

The technique will work for most women, but not if they are taking the contraceptive pill.

Dr Wallace and Dr Kelsey are currently involved in clinical studies of young women who have been successfully treated for cancer, and talking to GPs and fertility clinics.

They are also setting up long-term studies to follow young healthy women with regular assessments of ovarian volume until they reach the menopause.

The Equal Opportunities Commission said: "This kind of medical advance may help some women when they are planning their families. But women who want a career shouldn't have to weigh up the risk of 'leaving it too late' against staying in a job they enjoy. More and more employers are realising they can't afford to lose the talents of women who have children."