More research is needed to unravel the contradictory findings of large studies into the safety of hormone replacement therapy, says an expert.
Evidence on the impact on the heart is contradictory
Studies have linked the popular treatment with heart disease, stroke and breast cancer.
Shannon Amoils, of the journal BMJ Clinical Evidence, says the "jury is still out" on whether heart risks are less in women who take it in their 50s.
The British Heart Foundation advises against HRT to protect the heart.
Millions of women worldwide take HRT to relieve the symptoms of menopause, which can include hot flushes.
There is also evidence that longer-term use can reduce the chance of hip fractures in patients who are at risk.
Until recent years, it was also thought possible that taking the hormones could help reduce the chance of heart disease.
However, the findings of the Women's Health Initiative (WHI) study, the first large scale study which randomly looked at the effects of HRT on a large number of women, found significant links between certain types of HRT and breast cancer.
In addition, the WHI study revealed no heart benefits, and in fact an increased risk of heart disease and stroke in women taking HRT.
The WHI trial was halted prematurely in 2002 because it was felt that the women taking HRT were at unjustifiable risk.
Last month, however, the Journal of the American Medical Association published a second study, which looked again at the findings of the WHI study, and concluded that, while the heart risk existed for older women taking HRT, women aged between 50 and 59 might not be at risk.
In response, the International Menopause Study issued a statement suggesting that the issue of heart disease and HRT now seemed "irrelevant".
Shannon Amoils is not convinced by the latest study. She said that despite the large scale of the study, dividing into different age groups weakened it considerably.
"The number of cardiovascular events in each group is probably still too small to allow meaningful analysis," she said.
"In our opinion, the jury is still out on this controversial issue.
"Further high quality research, in the form of a large, long-term randomised controlled trial of HRT in women in the early menopause, is needed to assess conclusively the cardiovascular risks and benefits."
The British Heart Foundation agrees that the recent studies do not warrant changes to current guidelines on HRT.
"It should not be given primarily to reduce a woman's risk of developing coronary heart disease.
"The findings of this study were not statistically significant but several other studies are underway researching the hypothesis that if HRT is given either before, or immediately after the onset of the menopause, it may have some cardio-protective benefits."