By Michelle Roberts
BBC News health reporter
A large UK study has found using HRT significantly increases the risk of women developing ovarian cancer.
Women should calculate their own risks and benefits
Other studies have claimed HRT increases the risk of some cancers but protects against other conditions such as heart disease and osteoporosis.
Then other studies came along saying certain formulas posed no breast cancer risk but HRT's longer-term health benefits on the heart and bones were not clear, or its other risks outweighed any benefit.
So what are women to believe and what should they do?
BBC News spoke with medical experts to find out.
Half of women have stopped or been scared off using hormone replacement therapy (HRT) following the mixed reports, surveys in the US and New Zealand have shown.
UK doctors agree that many women are still worried about starting or continuing to use HRT.
The current advice by officials in the UK is that women should take the smallest possible dose for the shortest time to relieve symptoms of the menopause, such as flushes.
Any woman on HRT should be reviewed annually to check whether they should still be taking it.
This is because risks may begin to outweigh the benefits as use becomes longer, over years, says the Medicines and Healthcare products Regulatory Agency and the Committee on Safety of Medicines.
Although longer-term use does appear to protect against the bone wasting disease osteoporosis, HRT should only be used for this in women at highest risk of future fractures and who are unable to take other osteoporosis therapies.
Ultimately, the decision to continue or stop HRT should be made by the woman with the help and guidance of her doctor.
The risks and benefits will vary with the woman's age and medical history, such as whether she has a strong family history of breast cancer for example.
'Don't believe the hype'
However, not all experts agree with studies that the risk estimates are based on.
Some of the studies bear little resemblance to the majority of women who use HRT in the UK, they argue.
THE RISKS (per 1,000 women aged 50 and over)
After 5 years use of oestrogen-only HRT, 1-2 extra cases - 5 extra cases after 10 years use
After 5 years use of combined HRT, 6 extra cases - 10 after 10 years use
After 5 years use of oestrogen-only HRT, 4 extra cases - 10 extra cases after 10 years use
Data not available on combined HRT for 5 years use - less than 2 extra cases for 10 years use
After 5 years use of oestrogen-only HRT, 1 extra case - 3 extra cases after 10 years use
Risks with combined HRT use unknown
After 5 years of use of oestrogen-only or combined HRT, 1 extra case - 10-year data not available
After 5 years of use of oestrogen-only or combined HRT, four extra cases - 10-year date not available
Source: Medicines and Healthcare products Regulatory Agency
Mr David Sturdee, consultant obstetrician and gynaecologist at Solihull Hospital, said: "The important thing is to get it into perspective.
"So much of the publicity has been very emotive.
"Women should not generalise and assume that what they read in the paper applies to them because so often it does not."
For example, a large US study, called the Women's Health Initiative, looked at women who were much older - in their early 60s - and who were taking much higher doses of HRT than is used currently in the UK.
"The majority of women in this country are receiving treatment for hot flushes around the time of the menopause and, for them, there is every reason to believe that it is a perfectly acceptable and reasonable thing to do for a limited period of time.
"How long that time will be will vary for the individual."
He said that although longer HRT use did increase the risk of certain diseases such as breast cancer, the actual numbers involved for a whole population of women were small.
The risks an individual woman is prepared to take for symptom relief will vary, he said.
THE BENEFITS (per 1,000 women aged 50 and over)
After 5 years of use of oestrogen-only or combined HRT, one fewer case - 2 fewer cases after 10 years use
Hip bone fractures (osteoporosis)
After 5 years of use of oestrogen-only or combined HRT, none or 1 fewer case - 1 fewer case after 10 years
Source: Medicines and Healthcare products Regulatory Agency
There is also conflicting advice about the risks with different formulations of HRT - oestrogen-only or combined (progesterone plus oestrogen).
Some research has suggested oestrogen-only HRT did not increase breast cancer risk, while other studies said it did.
Professor David Purdie, from the Edinburgh Osteoporosis Centre, said: "Women are thoroughly confused by the evidence that has been presented to them."
He believes some women may benefit from longer use of HRT to prevent osteoporosis, even though guidance only advises it is used if women also have menopausal symptoms.
How long is too long?
The Royal College of Obstetricians and Gynaecologists said: "Most women use HRT for menopausal symptoms for less than five years.
"However, young women with premature menopause can continue up to the age of the normal menopause (51 years) before considering whether they too, on a risk-benefit balance, wish to continue for longer.
"The small group of women who experience very severe symptoms impacting on their quality of life, should, with the aid of health professionals consider the pros and cons of ongoing hormone therapy.
"Many such women may decide to continue HRT, accepting small increases in risk."
Dr June Raine from the MHRA said it was important for women to weigh up their own risks and benefits with the help of their doctor when deciding whether to begin, continue or stop treatment.
"It has to be an individual decision. Only the woman can make up her mind about this on the best advice available and how she feels herself."
She advised women currently on HRT, "At your next available appointment, review your needs - are you on the lowest possible dose to control symptoms?
"If you come off and your symptoms come back then review the need to continue. It has to be judged in that way."
She said the MHRA was keeping on top of all the data as it came out and, with the advice of the CSM's Expert Working Group on HRT, updating its advice accordingly.
Dr Raine said she hoped and believed the drop in HRT use was because women were making well informed decisions about their treatment rather than being put off taking it by reports of adverse side effects.
She said some of these women were probably considering alternative ways of dealing with their menopausal symptoms and taking alternative osteoporosis therapies.