This is the news archive of Facts are Facts.
You can find our recent articles in the section Latest.
A venous thrombosis is a type of blood clot which can travel up the body to the lungs, blocking an artery - a potentially life-threatening condition. The research, reported in the Daily Mail and published in the Journal of the American Medical Association, was carried out in the United States.
It involved almost 17,000 post-menopausal women aged between 50 and 79. The study said that 167 women on HRT developed a venous thrombosis, compared to 76 taking a placebo pill. The researchers said that when they compared women in their 50s taking placebo, to those in their 60s on HRT they found a fourfold risk. The risk was seven times higher for women taking the treatment in their 70s.
The risk of developing a clot was also higher for women on HRT who were overweight or obese, the study found. The researchers concluded that HRT was associated with doubling the risk of venous thrombosis and that this risk increased still further with age or obesity.
This latest study involved a form of HRT taken only by women who have a womb, according to the Daily Mail. Dr John Stevenson, chairman of Women's Health Concern, told the newspaper that the extra risk of venous thrombosis for HRT users was well recognised. He said: "The risk of having a blood clot increases with age, regardless of HRT, and women using HRT are already counselled about it."
More than six million women in the UK are thought to have received HRT. However, large numbers are thought to have been scared away from the treatment following a series of health warnings.
In 2002, a Women's Health Initiative (WHI) study showed that far from protecting post-menopausal women, a common form of combined-hormone HRT actually increased the risk of heart attacks and strokes.
But earlier this year, experts raised doubts about the study and said women may have been misled about the effects of HRT.