Hormone replacement therapy (or menopausal hormone therapy) refers to oestrogen, progesterone and testosterone hormones (taken alone or in combination). It remains the most effective medical treatment for menopausal symptoms. However, its benefits need to be balanced against common possible side effects and long-term risks.
This article was included in issue 101 (Summer 2024) of The Menopause Exchange newsletter.
HRT hormones
Most commercially available HRT preparations contain 17 beta oestradiol, one of the plant-based natural forms of oestrogen. The use of horse (equine) oestrogen has declined in the past two decades, due to an increased risk of blood clots with its long-term use. Progestogens are natural or synthetic steroid hormones. These are combined with oestrogen in various HRT preparations. [Progestogens are covered in Issue 99.]
Combined HRT (oestrogen and progestogen) is prescribed if you have a uterus. Taking oestrogen alone can increase the chance of getting cancer of the uterine lining (endometrial cancer). Adding progestogen to oestrogen reduces this risk. Oestrogen-only HRT (no progestogen) is prescribed if you have had a hysterectomy. While oestrogen-only HRT is associated with no or minimal long-term risk of breast cancer, combined HRT is associated with a slightly increased risk of breast cancer (about 5 in 1000 extra cases over 5 years).
Taking HRT
You can take HRT in two ways:
Continuous combined HRT: oestrogen and progesterone, taken daily continuously, with no monthly withdrawal bleeds.
Sequential HRT: oestrogen only for the first 14 to 16 days and then both hormones for 12 to 14 days. This usually results in monthly withdrawal bleeds as it tries to copy the natural cycle and causes a period.
Cyclical HRT is often prescribed if you have menopausal symptoms but are still having periods, or stopped having periods less than one year ago. Continuous HRT (without bleeds) is more suitable if you haven’t had periods for more than one year.
Different HRT forms
HRT is available on prescription in several forms. These include:
- skin patches
- oral tablets
- capsules
- gel
- spray
- implants
- vaginal ring
- progestogen-releasing uterine coil
- vaginal cream
- pessaries
Some HRT forms work best for certain symptoms. The right formulation will usually be advised by your healthcare professional, taking on board your symptoms, preferences and medical history. This can be changed later if it doesn’t suit.
Transdermal oestrogen (patch/gel/spray/implant) is associated with a lower risk of blood clotting than oral HRT, and is preferable if you have diabetes, high blood pressure, high BMI, or other cardiovascular risk factors and are over 60. Body-identical or body-similar versions of progestogens, such as micronised natural progesterone or dydrogesterone, appear to be safer than synthetic versions and have a lower risk of blood clotting or breast cancer with long-term use.
Vaginal oestrogen creams or pessaries don’t carry the same risks as systemic oral or transdermal HRT. These are highly effective for vaginal dryness, painful sex, urinary frequency/incontinence, and repeated urinary infections. As the dose of oestrogen is low, they don’t require the protective effect of progestogen. The hormone coil (Mirena or levonorgestrel intrauterine system) can be used as the progesterone arm of HRT to protect the endometrium. It lasts for five years as HRT and provides contraception.
Body-identical versus bio-identical
Plant-based natural progesterone combined with 17 beta oestradiol is regulated body-identical HRT. It is commonly prescribed. Bio-identical HRT (compounded HRT preparations) are combinations of plant oestrogens and progesterone-like compounds formulated by individual clinics and pharmacies. These are currently not recommended in the UK by the British Menopause Society, as robust long-term safety data is lacking for many of these.
Tibolone
Tibolone is an oral synthetic steroid with oestrogenic, progestogenic and androgenic properties. It’s a form of bleed-free HRT and is indicated for menopausal symptoms and the prevention of bone loss during the menopause. Some studies have reported an improvement in sexual function or libido with the use of tibolone.
Testosterone
Testosterone can help people with a persistent lack of libido despite taking HRT containing oestrogen. Some also notice improved energy levels, better mood and less brain fogging on testosterone. However, more research is needed to confirm these benefits. Testosterone is available as gels, a cream and implant. It’s used in small doses and doesn’t usually cause side effects. Excessive use can cause oily skin, excess body hair, scalp hair loss and deepening of the voice.
New vaginal atrophy treatments
Two newer treatments for vaginal atrophy are oral ospemifene (a selective oestrogen receptor modulator) and vaginal pessaries with DHEA (dehydroepiandrosterone). [See Issue 100 for more information on new HRT products.]
About the author
Dr Vikram Talaulikar is an associate specialist in reproductive medicine and honorary associate professor in women’s health at University College London Reproductive Medicine Unit, University College London Hospital.
Created Summer 2024
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