According to new research the widely publicised 2002 study which apparently proved that hormone replacement therapy raised the risk of heart disease and breast cancer, was fundamentally flawed.
The publicity surrounding the study scared many women away from the drugs and women are still being told not to take hormones for heart disease prevention.
Dr. Edward Klaiber, a Worcester, Massachusetts endocrinologist and lead author of the new research says that may have been totally wrong.
Hormone replacement therapy was once widely advocated for women as they reached menopause in the belief that it would relieve unpleasant symptoms such hot flashes and night sweats while at the same time protecting against heart disease and osteoporosis.
Then in 2002, women taking estrogen and progestin were advised to stop taking the drug after the Women's Health Initiative (WHI) said a trial of Wyeth's Prempro showed that the drug raised the risk of heart attack, stroke and some forms of cancer.
Klaiber says Prempro combined estrogen and progestin in a daily pill combination never previously associated with heart protection.
He says that during the WHI trial concept, hormone replacement therapy usually involved cyclical progesterone, meaning that it was taken just 10 or 12 days a month.
But then the daily combined drug was thought more convenient because patients did not have to remember which days to take a second pill and because it eliminated a monthly menstrual period.
The researcher believes the results might have been different if a different form of estrogen that resembled a normal cycle had been used.
Even at the time many doctors considered the WHI study flawed in that the participants were almost all over 60 and so at greater risk of cardiovascular problems anyway.
Klaiber says the incidence of heart disease is 12 times higher for women in their 80s than it is in the 50s.
Therefore the WHI study began hormone therapy for the first time in women who already had heart disease - not a good idea.