In this article
For a while, hormone therapy was thought to protect women's hearts. Then a major trial suggested it might do the opposite. Today the answer sits somewhere in between, and it depends a lot on when you start. Here is what the research measured, and what it means for your decision.
The short answer
Hormone therapy is a treatment for menopause symptoms like hot flashes, not a heart medicine. The Menopause Society says it is not government approved for preventing heart disease, either before or after a first event [1]. The US Preventive Services Task Force recommends against using combined estrogen and progestin, or estrogen alone, to prevent chronic conditions in postmenopausal women, having found no net benefit for that purpose [8].
That does not mean hormone therapy harms every woman's heart. The question researchers have spent two decades on is when you start. For healthy women with symptoms who are under 60 or within 10 years of menopause, The Menopause Society says the favorable effects on heart disease and death from any cause should be weighed against rare increases in breast cancer, blood clots, and stroke [1].
What the WHI found
Despite decades of observational research, the balance of risks and benefits of hormone therapy was still uncertain in the 1990s, so the Women's Health Initiative (WHI) tested it in a randomized trial [2]. The combination trial enrolled 16,608 women aged 50 to 79 who had a uterus, and coronary heart disease was its main target outcome [2].
After an average of 5.2 years, researchers estimated 7 more coronary heart disease events, 8 more strokes, and 8 more pulmonary emboli per 10,000 women per year on the combination pill [2]. They concluded it should not be started or continued to prevent heart disease [2].
The estrogen-alone trial, in 10,739 women who had had a hysterectomy, found no effect on coronary heart disease but 12 more strokes per 10,000 women per year [10].
Longer analysis changed the picture for the combination somewhat. Across the full intervention phase, its effect on coronary heart disease was not statistically significant, and neither regimen changed death from any cause [4]. After 18 years of follow-up, hormone therapy in the trials was not linked to overall, cardiovascular, or cancer death [5].
The timing hypothesis
The average WHI participant was 63 [5]. That fact sits at the center of what is called the timing hypothesis: the idea that estrogen may affect the heart and blood vessels differently depending on whether it is started close to menopause or many years later [6].
In 2007, WHI researchers split their combined results by years since menopause [3]:
| Years since menopause | Hazard ratio vs placebo | Extra cases per 10,000 women per year |
|---|---|---|
| Less than 10 | 0.76 | 6 fewer |
| 10 to 19 | 1.10 | 4 more |
| 20 or more | 1.28 | 17 more |
A hazard ratio below 1 means fewer events than placebo, and above 1 means more. Only the 20-or-more group was clearly elevated, and the overall trend did not meet the researchers' own threshold for statistical significance [3]. So this analysis suggests a pattern rather than proving one.
Stroke behaved differently. Hormone therapy raised stroke risk, and the increase did not vary significantly by age or time since menopause [3].
Age showed a similar pattern for survival. In the pooled WHI trials, women who started hormones at 50 to 59 had lower death from any cause than placebo during the trials, while women in their 60s and 70s did not [1].
Testing the idea: ELITE and KEEPS
Two randomized trials set out to test timing directly. Both measured imaging markers of artery disease rather than heart attacks.
ELITE
The Early versus Late Intervention Trial with Estradiol enrolled 643 healthy postmenopausal women, grouped by whether they were less than 6 years or at least 10 years past menopause [6]. They took oral estradiol 1 mg a day, with progesterone vaginal gel for 10 days of each month if they had a uterus, or placebo [6].
After a median of 5 years, estradiol slowed thickening of the carotid artery wall, a marker of early atherosclerosis, in the early group but not in the late group [6]. Coronary CT scans for calcium and plaque did not differ between estradiol and placebo in either group [6].
KEEPS
The Kronos Early Estrogen Prevention Study enrolled 727 healthy women aged 42 to 58 who were 6 to 36 months past their last period [7]. For 4 years they took low-dose oral conjugated estrogens or a transdermal estradiol patch, each with oral progesterone 12 days a month, or placebo [7].
Artery wall thickening progressed at a similar rate in all three groups [7]. Some risk markers moved: cholesterol levels improved with oral estrogen, and insulin resistance decreased with the patch [7]. The authors noted the trial was too small to compare actual heart attacks or strokes [7].
- WHI, average age 63The combination pill added a small number of heart events.
- WHI, by timingA lower trend near menopause and higher risk 20 or more years later.
- ELITEEstradiol slowed artery thickening only when started early.
- KEEPSNo difference in artery thickening after 4 years.
Timing seems to matter. Prevention is still not the reason to take HRT.
Sources: WHI, JAMA 2002 and 2007; ELITE, N Engl J Med 2016; KEEPS, Ann Intern Med 2014; The Menopause Society 2022.
Put together, these studies suggest timing matters, but they do not show that hormones prevent heart attacks. The Menopause Society summarizes the trials in recently menopausal women as showing that hormone therapy reduced or had no effect on the progression of atherosclerosis [1].
If you are over 60 or far past menopause
The Menopause Society says women who start hormone therapy after 60, or more than 10 or 20 years after menopause, have higher absolute risks of heart disease, blood clots, and stroke than women who start in early menopause [1]. In a 2015 Cochrane analysis it cites, starting hormone therapy more than 10 years after menopause had no effect on heart disease or death but raised the risk of stroke and clots [1].
Women who already had heart disease were studied in HERS, a trial of 2,763 women with an average age of 66.7 [9]. In the first year, there were more heart events on estrogen plus a progestin than on placebo, though rates were similar for the rest of the study [9].
What FDA labels say now
In February 2026, updated FDA labeling for an approved estradiol and progesterone capsule removed cardiovascular disorders from its boxed warning [9]. The heart and stroke risks moved rather than disappeared: they remain in the Warnings and Precautions section [9].
One updated label advises considering starting therapy in women under 60 or within 10 years of menopause onset [9]. It reports that among women aged 50 to 59 in the WHI combination trial, there were 5 extra coronary events and 5 extra strokes per 10,000 women per year, neither statistically significant [9]. The label also says the product's safety and effectiveness for preventing cardiovascular disorders have not been established, and it lists a past stroke or heart attack as a contraindication [9].
Questions to bring to your clinician
- How long ago was my last period, and does that change my options?
- What do my blood pressure, cholesterol, and blood sugar mean for this decision?
- Is there anything in my personal or family history of heart disease or stroke you would want to know?
- Would a lower dose or a non-oral route make sense for me?
- How often will we review whether to continue?
The Menopause Society advises considering personal and family risk of heart disease, stroke, and clots before starting hormones [1]. Hormone therapy remains the most effective treatment for hot flashes and night sweats [1]. For a broader look at the trade-offs, read is HRT safe?, and for clots specifically, HRT and blood clots.
Talking it through with WarriorBabe Health
A WarriorBabe Health clinician reviews your heart and stroke history, and your family's, before deciding whether hormone therapy makes sense for you. Options include oral estradiol, an estradiol patch, estradiol cream, and a progesterone capsule for women with a uterus. Compare them on our hormone treatments page.
Our hormone products are compounded by a licensed pharmacy. Compounded drugs are not FDA-approved, which means the FDA does not review their safety, effectiveness, or quality before they are marketed [11]. The studies in this article tested approved products, so ask your clinician how they apply to you.
Want to know whether hormone therapy might fit? Take the 2-minute quiz. A licensed clinician makes the final call on whether any prescription is appropriate.
Frequently asked questions
Does HRT cause heart disease?
It depends heavily on age and timing. In the original WHI combination trial, with an average participant age of 63, there were 7 more heart events per 10,000 women per year [2, 5]. When results were split by time since menopause, risk tended to be lower in women within 10 years of menopause and higher in women 20 or more years out [3].
Can HRT protect my heart if I start early?
That has not been shown. The Menopause Society notes observational data and meta-analyses suggest lower heart disease risk with early starts, but hormone therapy is not approved to prevent heart disease [1]. In the ELITE trial, early estradiol slowed artery thickening but did not change coronary CT findings [6].
What is the timing hypothesis?
It is the idea that estrogen may affect blood vessels differently depending on whether it is started near menopause or many years later [6]. ELITE supported it for artery wall thickening [6]. KEEPS, in recently menopausal women, found no effect on artery thickening either way [7].
Can I take HRT if I have had a heart attack or stroke?
FDA labeling lists a current or past heart attack or stroke as a contraindication for estrogen plus progestogen [9], and The Menopause Society lists prior coronary heart disease, stroke, or heart attack among contraindications for oral and transdermal hormone therapy [1]. Your clinician can discuss other options.
Does HRT raise stroke risk?
In the WHI, hormone therapy raised stroke risk, and the increase did not vary significantly by age [3]. For women who started combination therapy before 60 or within 10 years of menopause, The Menopause Society describes the added risk as rare, about 5 per 10,000 women per year [1].
References
- The 2022 hormone therapy position statement of The North American Menopause Society. Menopause. 2022;29(7):767-794. menopause.org/wp-content/uploads/professional/nams-2022-hormone-therapy-position-statement.pdf
- Rossouw JE, Anderson GL, Prentice RL, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women's Health Initiative randomized controlled trial. JAMA. 2002;288(3):321-333. pubmed.ncbi.nlm.nih.gov/12117397/
- Rossouw JE, Prentice RL, Manson JE, et al. Postmenopausal hormone therapy and risk of cardiovascular disease by age and years since menopause. JAMA. 2007;297(13):1465-1477. pubmed.ncbi.nlm.nih.gov/17405972/
- Manson JE, Chlebowski RT, Stefanick ML, et al. Menopausal hormone therapy and health outcomes during the intervention and extended poststopping phases of the Women's Health Initiative randomized trials. JAMA. 2013;310(13):1353-1368. pubmed.ncbi.nlm.nih.gov/24084921/
- Manson JE, Aragaki AK, Rossouw JE, et al. Menopausal hormone therapy and long-term all-cause and cause-specific mortality: the Women's Health Initiative randomized trials. JAMA. 2017;318(10):927-938. pubmed.ncbi.nlm.nih.gov/28898378/
- Hodis HN, Mack WJ, Henderson VW, et al. Vascular effects of early versus late postmenopausal treatment with estradiol. N Engl J Med. 2016;374(13):1221-1231. pubmed.ncbi.nlm.nih.gov/27028912/
- Harman SM, Black DM, Naftolin F, et al. Arterial imaging outcomes and cardiovascular risk factors in recently menopausal women: a randomized trial. Ann Intern Med. 2014;161(4):249-260. pubmed.ncbi.nlm.nih.gov/25069991/
- US Preventive Services Task Force. Hormone therapy for the primary prevention of chronic conditions in postmenopausal persons: US Preventive Services Task Force recommendation statement. JAMA. 2022;328(17):1740-1746. pubmed.ncbi.nlm.nih.gov/36318127/
- Mayne Pharma. Bijuva (estradiol and progesterone) capsules prescribing information. DailyMed, US National Library of Medicine. Revised 2026. dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=59eadb88-c9f3-4871-b176-7ddd98faf9bc
- Anderson GL, Limacher M, Assaf AR, et al. Effects of conjugated equine estrogen in postmenopausal women with hysterectomy: the Women's Health Initiative randomized controlled trial. JAMA. 2004;291(14):1701-1712. pubmed.ncbi.nlm.nih.gov/15082697/
- US Food and Drug Administration. Understanding the risks of compounded drugs. www.fda.gov/drugs/human-drug-compounding/understanding-risks-compounded-drugs
This article is for general information. It is not medical advice and does not replace a visit with a licensed clinician who knows your history. Do not start, stop or change a medication without talking to your clinician. If you think you are having a medical emergency, call 911.
