The symmetry is neat:a million women in the UK have reportedly stopped taking hormone replacement therapy (HRT) thanks to the Million Women Study. This investigation from 2003 concluded that women on HRT demonstrated a twofold risk of breast cancer.

The study, along with a report by the US Women’s Health Initiative (in 2002) which linked HRT to a twofold risk of heart disease, sparked such fear that the number of prescriptions issued fell from six million in 2001 to three million by 2005. The figure is now closer to 2.5 million.

In February this year, the European Journal of Cancer revealed that in 2000 more than 40 per cent of women aged 50-54 were taking HRT, and the figure was more than 35 per cent in the 55-59 age group. By 2006, HRT the number of users among 50-54 year olds had dropped to around 20 per cent, and among 55-59 year olds the percentage was down to 15 per cent.

Experts at Cancer Research UK believe there is a direct correlation between the fall in the number of women taking HRT and the number diagnosed with breast cancer. Their statistics show a drop of nine per cent among women aged 50-54 and a fall of five per cent in the older age group. (Other researchers have attributed the decrease to the success of the NHS breast-screening programme.)

Now, however, GPs and gynecologists are warning that the pendulum has swung too far. They say that hundreds of thousands of women who would benefit hugely from HRT are being denied the safe help they need. They argue that a possible increased risk of breast cancer is not the only factor that should be considered. Women need to know that replacement oestrogen can prevent osteoporosis, uterine cancer and heart disease in certain risk groups, while alleviating menopausal symptoms that range from hot flushes and mood swings, to a depressed libido, and insomnia – both of which can have a devastating impact on women’s lives.

HRT was developed to counter the fall in levels of oestrogen and progesterone that occur when a woman enters the menopause. The average age of the menopause is 51, although there are huge variations. It is still a relatively new science and it remains highly controversial. The first menopause clinic in Britain was set up in Birmingham only 40 years ago by Professor John Studd. He takes issue with the studies that have dissuaded so many women from using HRT.

"I would disregard all the WHI 2002 data concerning women aged under 60 because the side-effects reported were age-related and occurring in women over 70 who started HRT using too high a doseof a combined oestrogen progesterone therapy no longer in use. Some of the original investigators are now going over their findings and changing their minds. The Million Women Study has been utterly discredited because of eccentric collection of data, relying as it does on a single questionnaire, rather than in a clinical trial," he says.

"HRT is very, very safe – certainly in women under 60. There is almost no evidence that HRT is dangerous for women below that age. In fact, it is very important for them. HRT deals with the main symptoms of menopause and, for women who are losing bone density, oestrogen therapy is also the best way to prevent the onset of osteoporosis in 20 years time.

"Too many women are no longer offered HRT. They are instead being prescribed the antidepressant drug Prozac to cope with depression, and Fosimax, a drug to build up bones. Both of these have many side effects," he adds.

Professor Valerie Beral, director of Cancer Research UK, disagrees and defends the Million Women Study. "Women taking HRT have an increased chance of developing breast cancer. They also have a slight increase in the risk of ovarian cancer, stroke and blood clots," she says.

She points out that since 2002, Britain’s Medicines and Health care Products Regulatory Agency and its counterparts in Europe and the US have advised that women taking HRT should take it for as short a time as possible and in the lowest possible dose, to relieve symptoms.