Menopause treatment · absolute risks
NICE estimates for women who start treatment at 50: 92 breast cancers per 1,000, against 59 without HRT. The same estimates show the other side: with any HRT taken for ten years, 47 fewer fragility fractures by age 59. The window, the type of treatment and how long the effect lasts all differ, so one number cannot be subtracted from the other. What they show is the thing missing from both “HRT is safe” and “HRT is dangerous”: the size. And the size changes with the type of hormone, the route and the age at which you start.
A thousand women
Each dot is a woman. Filled dots are the cases estimated for 1,000 women without HRT. The extra coloured ones are the estimated difference in the group taking the treatment. Empty green rings show by how many cases the estimate is lower in the treated group. The grid compares two groups of 1,000 women; it does not say which woman is affected.
Source: NICE, HRT and the likelihood of some medical conditions, a discussion aid (NG23, 2024). The numbers are estimates for the UK population, not predictions for any one person, and they apply to licensed doses. Combined HRT means oestrogen plus a progestogen; NICE recommends oestrogen alone after a total hysterectomy.
Why take it
Nobody takes HRT to move the dots above. They take it for hot flushes, night sweats, broken sleep and the other symptoms that can last for years. For hot flushes and night sweats, NICE recommends offering HRT; as alternatives it names cognitive behavioural therapy and, when HRT is not suitable, fezolinetant. For vaginal dryness and irritation, low-dose local oestrogen is a separate decision, with very little exposure for the rest of the body.
So the useful question is a different one: how much does the treatment help me, against how much it adds, for this type, by this route, at my age? Type, route and age each move the numbers.
Type of hormone
Oestrogen alone, taken by a woman who has a womb, thickens its lining and raises the risk of womb (endometrial) cancer. So when the womb is present, oestrogen is paired with a progestogen. The price of that protection shows up in the breast: over ten years, +33 per 1,000 with combined HRT, against +12 with oestrogen alone.
Breast cancer, ages 50–69
Per 1,000 women: 59 without HRT, 79 after five years of combined HRT, 92 after ten. Oestrogen alone: 69 and 71. NICE says the risk rises with duration, is higher while treatment is being taken, falls after stopping but persists for at least ten years.
Womb cancer, ages 50–54
Continuous combined HRT, with a progestogen every day, lowers the risk: 1 case per 1,000, against 4 without HRT. The sequential regimen, with a progestogen for part of the month, takes it to 8. Oestrogen alone in a woman with a womb, to 11.
Sequential or continuous
NICE: breast cancer risk is lower with the sequential regimen than with the continuous one, but higher than without HRT. For the womb, the order is reversed. There is not enough evidence that micronised progesterone or dydrogesterone changes the breast risk compared with other progestogens.
Route
NICE finds that oral therapy raises the risk of venous thromboembolism, clots in the veins that can travel to the lungs. A patch, gel or spray on the skin does not. For people at higher risk of clots, including those with a body mass index over 30, NICE recommends considering the transdermal route.
For stroke, the baseline risk under 60 is very low: 3 in 1,000 between 50 and 54. NICE says transdermal oestrogen is unlikely to raise it. Oral oestrogen does, more so at higher doses. With oral combined HRT, the risk also rises with the length of treatment and the age at which it starts; with oral oestrogen alone, especially if treatment starts after 60. With oral oestrogen alone, the difference shows up on the grid as one dot: from 3 to 4.
For clots, NICE gives no per-1,000 numbers; the wording comes from the NG23 recommendations.
Timing
Dementia, started at 65 or later
In a randomised trial of women who started combined HRT at 65 or later, dementia cases doubled. For women who start in their fifties, NICE calls the data inconclusive. HRT is not prescribed to prevent dementia.
Heart
At 50–54, coronary heart disease: 9 per 1,000 without HRT, 10 with combined HRT, a difference that may be down to chance. NICE says HRT does not raise the risk of coronary heart disease and is not offered to prevent heart disease.
Life expectancy
NICE asks doctors to explain that, overall, combined or oestrogen-only HRT is unlikely to affect life expectancy.
Menopause at 40–44
Between 40 and 59, breast cancer: 33 per 1,000 without HRT, 51 after ten years of combined HRT, 41 with oestrogen alone. For fractures, heart, womb or ovaries, NICE found no data at this age. Under 40, premature ovarian insufficiency follows a different logic: HRT replaces hormones that would otherwise still be present.
What it isn't
Pregnancy is still possible in perimenopause. HRT does not prevent it; contraception is a separate conversation.
NICE: HRT is not offered for primary or secondary prevention of cardiovascular disease.
NICE: HRT is not offered for the purpose of preventing dementia.
It does not change weight as such. What happens to the body at menopause is on the weight page.
At the appointment
Sources
Sources rechecked 27 September 2026 · No independent clinical review · Not a substitute for a consultation