Hormone Therapy at Menopause: Who Is It Suitable For? The Current Scientific Approach

Hormone therapy at menopause has been one of the most debated topics in women’s health ever since the first results of the Women’s Health Initiative (WHI) study. Since then, the data have been reanalysed by age group and 20-year follow-up results have been published. Today the 2022 position statement of the North American Menopause Society (NAMS; now called The Menopause Society), England’s NICE NG23 guideline and the Türkiye Menopoz ve Osteoporoz Derneği (TMOD, the Turkish Menopause and Osteoporosis Society) agree on the same basic principle: menopausal hormone therapy (MHT) is not for everyone, but when started in the right person at the right time, it is an option whose benefits outweigh its risks ^1,2,3.

What is menopausal hormone therapy, and what does it treat?

Menopausal hormone therapy means giving, as a medicine, the oestrogen that the ovaries have stopped producing. In women who still have their womb (uterus), a progestogen (a second hormone that protects the lining of the womb) is always added to systemic (acting on the whole body) oestrogen, because unopposed oestrogen increases the risk of cancer in the womb lining (endometrium), and adequate progestogen markedly reduces this risk ¹. The type of regimen (continuous or sequential) and the length of use also affect this risk ². The medicine can be given as tablets taken by mouth, patches applied to the skin, gel or spray; low-dose vaginal oestrogen used only for vaginal symptoms does not require a progestogen ¹.

According to NAMS 2022, hormone therapy is the most effective treatment for vasomotor symptoms such as hot flushes and night sweats, and for genitourinary syndrome of menopause (GSM; vaginal dryness, painful intercourse and urinary symptoms at the menopause), and it has been shown to prevent bone loss and fractures ¹. NICE also recommends offering hormone therapy as an option to women with vasomotor symptoms associated with the menopause ². These three areas — hot flushes, GSM and bone — are the main reasons for treatment ¹; everything else is discussed around these reasons.

Why does timing matter so much?

Timing is the key to the current approach. NAMS 2022 states that for women who are younger than 60 or within the first 10 years after the onset of menopause, and who have no contraindications (conditions that rule out treatment), the benefit–risk balance is favourable for treating bothersome hot flushes and preventing bone loss ¹. TMOD also states that, before the age of 60 and in the first 10 years after the menopause, hormone therapy is the most effective treatment for vasomotor symptoms ³.

The picture changes when the same treatment is started late. For women who start more than 10 years after the menopause or after the age of 60, the benefit–risk balance is less favourable, because the absolute risks of coronary heart disease, stroke, blood clots in the veins (venous thromboembolism) and dementia are higher ¹. The International Menopause Society (IMS) 2024 White Paper also places the questions “who, which treatment, when” at the centre of prescribing ⁴. So the question “is hormone therapy good or bad?” has no simple answer; the answer depends on the person and the timing.

Who is it suitable for, and who is it not?

Suitable candidates are usually: women with hot flushes and night sweats that disrupt daily life, women at high risk of fracture who need bone protection, and women with premature ovarian insufficiency (POI), in whom ovarian function becomes insufficient before the age of 40 ^1,5. For POI, the ESHRE/ASRM/IMS 2024 guideline recommends continuing hormone therapy at least until the usual age of menopause, whether or not there are symptoms, to reduce risks to bone, cardiovascular and general health ⁵; NAMS gives the average age of menopause as about 52, and TJOD gives about 47–49 for Türkiye ^1,6. After this age, the decision to continue is made on the basis of an individual benefit–risk assessment ⁵.

The contraindications — situations in which the treatment should not be given — are also clear: unexplained vaginal bleeding, liver disease, a previous oestrogen-sensitive cancer (including breast cancer), previous coronary heart disease, heart attack, stroke or blood clot in a vein, and an inherited high risk of blood clotting ¹. Systemic hormone therapy is not usually recommended for women who have had breast cancer ^1,3. Another limit concerns purpose: in 2022 the US Preventive Services Task Force (USPSTF) recommended against using hormone therapy to prevent chronic disease; this recommendation does not cover the treatment of symptoms such as hot flushes ⁷.

How large is the breast cancer risk in reality?

The most feared issue is breast cancer, and the figures should be read in context. In the WHI study, which included women aged 50–79, those using combined oestrogen–progestogen had 9 additional cases of breast cancer per 10,000 woman-years; NAMS classifies this level as “rare” (fewer than 10 per 10,000 woman-years) ¹. In women whose womb had been removed and who took oestrogen alone, the same study found no increase, and a reduction in risk was reported at 20-year follow-up ¹. However, observational studies have found a small increase related to duration of use with oestrogen alone as well; NICE summarises this as “little or no increase” ^1,2.

The risk increases with duration of use; it decreases after stopping, but according to NICE it may remain somewhat raised for at least 10 years ^2,3. NAMS notes that this risk is of a similar size to that of modifiable factors such as two glasses of alcohol a day, obesity or an inactive lifestyle, and recommends this perspective in counselling ¹. This is not to downplay the risk, but to compare it on the right scale. NICE also asks that the options — combined or oestrogen-only, by mouth or through the skin, dose and duration — are discussed with each woman according to her age and risk factors ². The decision is a shared one that brings together the woman’s values and the doctor’s knowledge ^2,8.

How are the dose, route and duration decided?

The route of administration changes the risk profile. In observational studies, oestrogen given through the skin (transdermal) has not been associated with a risk of blood clots in the veins and suggests a lower risk than the oral form; however, comparative randomised (participants allocated to groups by chance) data are lacking ¹. NICE recommends considering the transdermal form rather than the oral form for women at increased risk of blood clots — for example, those with a body mass index over 30 ². The dose should suit the treatment goal and is often the lowest effective dose ¹.

There is no arbitrary upper limit on duration. Frequent hot flushes last an average of 7.4 years and continue for more than 10 years in many women; for this reason, an automatic age-based rule for stopping is not considered clinically appropriate ¹. Instead, the likely duration is discussed when treatment starts, benefits and risks are reassessed at every review, and it is explained that symptoms may return after stopping ^1,2. For unlicensed “bioidentical” hormone mixtures prepared individually in pharmacies, NAMS states that there is no evidence to support their general use and raises safety concerns; NICE states that their effectiveness and safety are not known ^1,2.

Evidence-based options for those who do not want hormones

Women for whom hormone therapy is unsuitable, or who do not want it, are not without options. The NAMS 2023 position statement recommends the following options for hot flushes at Level I (good and consistent evidence): a cognitive behavioural approach, clinical hypnosis, certain groups of antidepressants, an active ingredient from the anti-seizure medicine group, and a new class of medicine called neurokinin-3 receptor antagonists ⁹. NICE also recommends a menopause-specific cognitive behavioural approach in addition to, or instead of, hormone therapy ². The suitability of prescription options is determined at the consultation.

The same statement does not recommend herbal supplements, soya products, acupuncture, yoga, avoiding triggers or cooling techniques for treating hot flushes; the evidence is insufficient or inconsistent ⁹. It is also important to be realistic about brain health: NAMS does not recommend hormone therapy at any age to prevent cognitive decline or dementia ¹; the KEEPS follow-up showed that treatment used for 4 years at the start of the menopause brought neither benefit nor harm to cognition about 10 years later ¹⁰. The Lancet 2024 series likewise treats the menopause not as a hormone deficiency disease but as a stage of life managed with accurate information and shared decision-making ⁸.

If you have symptoms, please consult an obstetrics and gynaecology specialist.