The results in 2002 of a large U.S. study on hormone replacement therapy (HRT) in many respects left women confused and alarmed about the treatment for the menopause.

At that time the Women’s Health Initiative (WHI) study indicated that women taking Prempro, a popular combination of synthetic estrogen and progesterone, increased their risk of heart attacks and breast cancer, while decreasing the chance of colon cancer and bone fractures.

It advised that postmenopausal women should not take hormones for disease prevention, as opposed to relief from menopausal symptoms, because the risks outweighed the benefits.

However the same was not true for women who had undergone a hysterectomy as they were found to have significantly increased rates of stroke and blood clots, but a lower risk of breast cancer and hip fracture.

Overall the lingering impression was that HRT was essentially not a good thing, even though the total number of hormone-therapy users affected by the risks or benefits were small.

The average age for menopause in the U.S. is 51, but for the vast majority of women it occurs between 44 and 56.

Around 1 percent of women experience a ‘perimenopause’ before age 40 when menstrual periods start to become irregular and ends one year after they stop altogether.

Perimenopause, which for the average woman starts at age 46, usually lasts from two to eight years.

For the average woman, fertility begins to decline around age 37, but women who don’t want to get pregnant should continue to use contraception until they are definitely postmenopausal.

Scientists now know that it is the fluctuation in hormone levels which cause the hot flashes of the menopause which are more common in early postmenopause than in perimenopause, which eventually peter out.

Acne and thinning hair sometimes reflect hormonal changes, but can stop after hormone levels settle down.

However osteoporosis and vaginal thinning are more likely to get worse with age, unless women take estrogen.

Since 2002 hormone replacement therapy and its use has significantly changed and numerous remedies have hit the market, offering a range of treatments to treat the symptoms of menopause, which has left many women in a state of confusion and vulnerable to what is often unqualified advice.

Many of the so-called ‘non-drug’ or ‘natural’ alternatives are themselves harmful and lack any regulated track history.

The popular “bio-identical hormones” currently being advocated on the internet and by some celebrities as being ‘natural’ with the ability to replicate the body’s naturally produced estrogen, are in reality chemically produced hormones.

A bio-identical hormone is a custom-made recipe containing hormones in differing amounts and are often produced as creams, gels, liquids or sprays which often contain several other ingredients.

Such custom made compounds are not as a rule regulated or approved by health authorities and there is little data on safety, efficacy, manufacturing standards and no check on the veracity or accuracy of advertising claims.

The U.S. Food and Drug Administration in a survey of 29 such products for quality, sterility, identity, potency and uniformity of content, failed as many as 34 per cent on one or more tests and 25 per cent of the compounded hormones failed a potency test.

Experts remain in disagreement on how long it’s safe to take hormones, some say forever, others say a year or two, and a few say never.