Body-Identical Hormone Therapy

What are body-identical hormones?

Body-identical hormones have a chemical structure similar to the hormones produced by the human ovary. Two advantages over synthetic, non-body-identical options have been described:

• A more neutral effect on the risk of blood clots
• A more neutral effect on the risk of breast cancer

Which hormones are used?

Oestrogen

This is the main component of hormone therapy and is effective in controlling menopausal symptoms. It can be given in two ways:

• By mouth (tablet)
• Through the skin (transdermal): patch, gel or spray

Oestrogen given through the skin has a very neutral effect on the way the body breaks hormones down, and does not increase the risk of clots compared with not being on treatment. For people at higher risk of clots — for example those who are overweight or who have a high background risk — the skin route is therefore the one to prefer.

Because absorption varies from person to person, the dose is adjusted until the right level is reached. Three questions guide that: how much oestrogen is being given, how much of it is being absorbed, and how much the person needs for their symptoms to be controlled.

Progesterone / progestogen

For people whose womb has not been removed, this is always given to protect the lining of the womb from the effect of oestrogen. It can be given in two ways: so as to produce a monthly bleed (for people in perimenopause who are still having periods), or continuously without a monthly bleed (for people who have reached the menopause).

Micronised progesterone is plant-derived and similar in chemical structure to the progesterone the human ovary produces — that is, it is body-identical. Its advantages over synthetic progestogens are a neutral effect on clot risk and, in theory, a slightly lower breast cancer risk.

Synthetic progestogens are available as a tablet, a patch or an intrauterine device.

Testosterone

At replacement doses appropriate for women, testosterone is effective in improving low sexual desire. At physiological doses for women, unwanted effects are not expected, and it may be considered when oestrogen does not resolve this symptom. Its use is supported by the 2019 international consensus statement and by the British Menopause Society.

Why does hormone therapy matter?

Hormone therapy is the approach most often used and shown to be most effective in managing menopausal symptoms. It has been shown to produce clear improvement in symptom control and in quality of life. Beyond that it has two long-term effects:

Bone health

It has been shown to improve bone density appreciably and to protect against osteoporosis and the fractures that follow from it. This matters because hot flushes or vaginal dryness are noticeable symptoms, whereas osteoporosis has no clear symptom — the first sign may be a fracture.

Heart health and timing

Hormone therapy started under the age of 60 or within the first 10 years after the menopause has been shown to produce a clear reduction in the risk of heart disease and in deaths from cardiovascular disease. This is where the idea that the timing of treatment affects the outcome comes from.

How large is the breast cancer risk really?

This is the heading that causes the most concern, so it matters that the numbers are understood in context.

• Combined treatment containing oestrogen and a progestogen is associated with a small increase in breast cancer risk. That increase is low both medically and statistically.
• For oestrogen-only treatment (in people whose womb has been removed), little or no increase in breast cancer risk has been shown.
• A family history of breast cancer may raise a person's background risk but is not a barrier to taking hormone therapy.

For context, the guideline offers these comparisons: the breast cancer risk from two units of alcohol every evening is higher than the risk from hormone therapy. The risk from being overweight is markedly higher than that from hormone therapy.

For most people the improvement in quality of life, the reduction in osteoporosis risk and the reduction in heart disease risk outweigh the small increase in breast cancer risk. A lower death rate has been reported in people taking hormone therapy compared with those who are not.

Even so, the decision whether to take it and for how long should be made individually, after the benefits and risks have been discussed.

Options other than hormone therapy

Lifestyle: regular exercise, a diet low in saturated fat and salt and rich in calcium and vitamin D, stopping smoking and cutting down alcohol improve both symptoms and heart and bone health. Smoking has been shown to bring the menopause on earlier and to trigger hot flushes.

Cognitive behavioural therapy: an effective option for improving hot flushes, night sweats and other symptoms; it can be considered for people who do not want, or cannot take, hormone therapy.

Complementary methods: acupuncture, aromatherapy, herbal treatments, homeopathy, yoga and reflexology may help with symptoms; but most are less effective than hormone therapy at controlling symptoms and are not expected to have a clear effect on bone strength or heart health.