# HRT risks in numbers per 1,000 · Unpaused > Source: https://unpaused.cc/articles/hrt-risks-in-plain-numbers-breast-cancer-clots-and-stroke-per-1-000-women Hormone therapy ## HRT risks in plain numbers: extra cases per 1,000 The clearest benefits are fewer hot flushes, better sleep and stronger bones. The risk of breast cancer, blood clots and stroke depends on the type of HRT, whether you take it as a tablet, a patch or a gel, and whether you use it for 5 or 10 years. By Ines Kovac. Published 17 October 2026\. 8 minute read. The pros and cons of hormone replacement therapy (HRT) depend on what you take and for how long. Hot flushes, night sweats, sleep problems and bone strength are where treatment helps most clearly. Whether breast cancer, a blood clot in a vein, or stroke becomes more common depends on whether you take oestrogen alone or with a progestogen, whether you use a tablet, patch or gel, and how many years you stay on it. The picker counts extra cases in a group of 1,000 women who start around age 50, set against women who do not take HRT. Breast cancer totals and the stroke baseline come from the [NICE NG23 discussion aid](https://www.nice.org.uk/guidance/ng23/resources/incidence-of-medical-conditions-with-and-without-hrt-a-discussion-aid-pdf-13553199901) (November 2024). A second breast cancer line comes from the [MHRA drug safety update of August 2019](https://www.gov.uk/drug-safety-update/hormone-replacement-therapy-hrt-further-information-on-the-known-increased-risk-of-breast-cancer-with-hrt-and-its-persistence-after-stopping), drawn from a Lancet reanalysis. That line splits combined HRT into sequential and continuous, and it starts from a different baseline. Keep the two lines apart. Adding them double-counts the same women. The figures describe women with no personal history of breast cancer, stroke or a blood clot in a vein (venous thromboembolism, VTE). They are general information for a conversation with a clinician. ### Extra cases for your regimen Choose the type, the route and 5 or 10 years. Breast cancer figures start from age 50, matching the discussion aid. Other age groups need different tables, so the picker asks only for type, route and years. HRT type Oestrogen only Combined, sequential (progestogen for part of each month) Combined, continuous (progestogen every day) Route Tablet (by mouth) Patch or gel (through the skin) Years of use 5 years 10 years An estimate for a group, using the NICE discussion aid and the MHRA 2019 update. It is not a prediction for one woman. Show extra cases The counts appear here after you choose a type, a route and the years. ### A patch for five years, and a tablet for ten Breast cancer counts in this section use a group of 1,000 women, from age 50 to 69, which is the window in the discussion aid. Here is one worked example. A woman aged 52 uses combined HRT as a patch or gel for 5 years. The discussion aid begins at age 50\. At 52, she is inside the ages it covers. On the NICE chart, 79 develop breast cancer by 69, which is 20 more than the 59 with no HRT. The chart keeps all combined HRT on one row. The MHRA update breaks combined HRT into two regimens. Against a baseline of 63 women who never used HRT, about 14 extra cases follow sequential combined HRT for 5 years, and about 20 follow continuous combined HRT. Stroke in that patch example uses a shorter window, ages 50 to 54 over 5 years: 3 women who never take HRT have a stroke. An increased risk of stroke is unlikely with a patch or gel, and any difference is too small to show as extra cases in a group this size. The aid describes the increase with oral oestrogen as statistically significant. The difference with a patch or gel is not significant in that aid. For clots, [NICE Table 1](https://www.nice.org.uk/guidance/ng23/resources/table-1-combined-hrt-versus-no-hrt-effect-on-specific-health-outcomes-pdf-13553206381) says VTE risk is not increased with transdermal HRT. Switch those combined regimens to a tablet for 10 years and the NICE breast cancer row moves to 92 by age 69, which is 33 more than with no HRT. The MHRA update says extra cases up to age 69 are approximately doubled at 10 years compared with 5, so the 5-year extras above become about 28 and about 40\. Keep the NICE figure of 33 extra cases on its own line, next to those roughly doubled MHRA figures. Oral oestrogen is where Table 1 says stroke risk increases, more so at a higher dose and when use runs past 5 years. The stroke baseline remains the 5-year window in the patch example. The aid does not give a stroke count for 10 years. Oral HRT is also where Table 1 says VTE risk is increased, and greater than with transdermal HRT. The 2024 table gives no clot count for the group. An older chapter of NG23 pooled tablets with transdermal HRT and estimated [9 more clots in the first year, and about 10 more over five years](https://www.ncbi.nlm.nih.gov/books/NBK343458/). Read those pooled counts with the tablet example. The 2024 table separates routes and stops at a qualitative label. Oestrogen-only HRT on the same NICE chart: 69 women after 5 years, 10 more than with no HRT, and 71 after 10 years, 12 more. The MHRA 5-year extra for oestrogen-only HRT is about 5\. If use lasts 10 years, that extra is approximately doubled, against the baseline of 63 in the combined example above. ### Benefits of hormone replacement therapy [NICE NG23](https://www.nice.org.uk/guidance/ng23/chapter/Recommendations) says to offer HRT as the most effective treatment for vasomotor symptoms: hot flushes and night sweats, also called hot flashes. The [NHS](https://www.nhs.uk/medicines/hormone-replacement-therapy-hrt/benefits-and-risks-of-hormone-replacement-therapy-hrt/) describes it as effective for those flushes and sweats, and for sleep problems, mood swings, anxiety and low mood, and vaginal dryness. It also notes that HRT helps prevent osteoporosis. [NICE](https://www.nice.org.uk/news/articles/discussion-aid-to-support-clinical-conversations-about-hrt-published-alongside-updated-guidance) says HRT has risks but is unlikely to increase or decrease overall life expectancy. The recommendations say not to use HRT to prevent cardiovascular disease or dementia. For many healthy women with symptoms who are under 60, or within 10 years of their last period, the [Menopause Society 2022 position statement](https://pubmed.ncbi.nlm.nih.gov/35797481/) finds the benefits generally outweigh the risks. The balance is less favourable when treatment starts later. Guides on HRT types and how a prescription is chosen are in our [hormone therapy](/topics/hrt) topic. Mood, sleep and vaginal changes are grouped under [menopause symptoms](/topics/symptoms). A sheet of how often each symptom shows up, to take into the appointment, is the [symptom checklist for your GP](/articles/menopause-symptom-checklist-to-print-and-take-to-your-gp). If a prescription is described as bioidentical, regulated body-identical HRT and compounded products are set apart in [bioidentical hormone replacement therapy](/articles/bioidentical-hormone-replacement-therapy). ### Cancer, clots and stroke Breast cancer risk is higher with combined HRT than with oestrogen-only HRT, and higher after 10 years than after 5\. The counts are in the examples above. [NICE Table 2](https://www.nice.org.uk/guidance/ng23/resources/table-2-oestrogen-only-hrt-versus-no-hrt-effect-on-specific-health-outcomes-pdf-13553206382), for women who have not themselves had breast cancer, describes oestrogen-only HRT as carrying very little or no increase in risk. The discussion aid is the NICE document that still puts a count on that row. Blood clot risk depends on how the oestrogen is taken. The patch example and the tablet example use the Table 1 wording: the risk increases with a tablet, it does not increase with a patch or gel, and it is greater for a tablet than for a patch or gel. Stroke risk is tied to oestrogen taken as a tablet. Table 1 says the baseline risk in women under 60 is very low. The ages 50 to 54 baseline is in the first example. An increase is unlikely when oestrogen is absorbed through the skin. The breast cancer figures above do not switch when you swap a tablet for a patch. Stroke and clot results do. That is how the two sources are built: breast cancer by regimen and years, clots and stroke by route. ### How these estimates were built The counts are population averages. These averages leave out women with breast cancer in the family, or a previous clot or stroke. Treatment choices belong in a clinical appointment. Our [editorial policy](/editorial-policy) sets out how health claims on this site are sourced. * [NICE NG23 recommendations](https://www.nice.org.uk/guidance/ng23/chapter/Recommendations) * [HRT discussion aid (NICE, November 2024)](https://www.nice.org.uk/guidance/ng23/resources/incidence-of-medical-conditions-with-and-without-hrt-a-discussion-aid-pdf-13553199901) * [NICE news note on the discussion aid](https://www.nice.org.uk/news/articles/discussion-aid-to-support-clinical-conversations-about-hrt-published-alongside-updated-guidance) * [NICE Table 1, combined HRT](https://www.nice.org.uk/guidance/ng23/resources/table-1-combined-hrt-versus-no-hrt-effect-on-specific-health-outcomes-pdf-13553206381) * [NICE Table 2, oestrogen-only HRT](https://www.nice.org.uk/guidance/ng23/resources/table-2-oestrogen-only-hrt-versus-no-hrt-effect-on-specific-health-outcomes-pdf-13553206382) * [MHRA drug safety update, August 2019](https://www.gov.uk/drug-safety-update/hormone-replacement-therapy-hrt-further-information-on-the-known-increased-risk-of-breast-cancer-with-hrt-and-its-persistence-after-stopping) * [NG23 long-term risks chapter (NCBI Bookshelf)](https://www.ncbi.nlm.nih.gov/books/NBK343458/) * [NHS: benefits and risks of HRT](https://www.nhs.uk/medicines/hormone-replacement-therapy-hrt/benefits-and-risks-of-hormone-replacement-therapy-hrt/) * [Menopause Society 2022 position statement](https://pubmed.ncbi.nlm.nih.gov/35797481/) ### My take I would read the NICE breast cancer line first, then the MHRA line under it, because sequential and continuous combined HRT are separated only on the second line. For clots and stroke, I would look at tablet versus patch before I looked at 5 years versus 10\. Those three lines are what I would take into an appointment, written down, ahead of a percentage in a headline. ### Quick answers Does HRT cause breast cancer in everyone? The charts describe groups, so most women in them never develop breast cancer either way. Oestrogen alone and a combined regimen sit in different places, and a personal history takes the conversation outside these averages. Are patches safer than tablets for clots? A patch or gel sits on a different clot row from a tablet. The tablet row is the increased one. Breast cancer lines on this page stay put when the route changes. What are the main benefits if the number of extra cases seems small? People take it for symptoms that wreck the day and the night: flushes, sweats, sleep, mood and vaginal dryness. Bone strength holds while treatment continues. Heading off heart disease or dementia is the use guidance rules out. Does this change anything about weight gain? Weight is a separate question. The trials sit in the guide linked under these answers, and they are about kilograms rather than cancer or clots. For weight, read [the guide on whether HRT causes weight gain](/articles/will-hormone-replacement-therapy-cause-weight-gain). Written by Ines Kovac Menopause guides: symptoms, HRT, sleep and everyday changes Ines Kovac writes the practical guides on Unpaused: perimenopause, symptoms, hormone therapy, sleep, hot flushes and weight. She builds each piece from NHS and NICE pages, The Menopause Society's position statements and the studies behind them, and links every claim a reader might want to check. She says plainly what the evidence supports and where it runs out, and she never tells a reader to start or stop a medicine. Any correction is noted on the page where the error occurred. [ikovac@unpaused.cc](mailto:ikovac@unpaused.cc) Last checked 2026-10-17 --- Plain, practical menopause advice Plain, practical guides to perimenopause and menopause: symptoms, hormone therapy, sleep, hot flashes, weight and food, each checked against health services and medical societies. [desk@unpaused.cc](mailto:desk@unpaused.cc) ### Topics * [Perimenopause](/topics/perimenopause) * [Symptoms](/topics/symptoms) * [Hormone therapy (HRT)](/topics/hrt) * [Hot flashes](/topics/hot-flashes) * [Sleep](/topics/sleep) * [Weight and diet](/topics/weight-and-diet) * [All guides](/articles) ### About us * [About](/about) * [Authors](/authors) * [Editorial policy](/editorial-policy) * [How we make money](/how-we-make-money) ### Legal * [Terms](/terms) * [Privacy](/privacy) * [Contact](/contact) Unpaused © 2026 Unpaused. General health information, written from sources we link. It does not replace advice from your own doctor, nurse or pharmacist. 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