Illustration of newspapers with headlines about hormones.

How one controversial study shaped 20 years of menopause care

July 21, 2025
Hone Health

How one controversial study shaped 20 years of menopause care

By now, many women navigating perimenopause or menopause know the headline: In 2002, a study linked hormone replacement therapy (HRT) to an increased risk of breast cancer. Overnight, women abandoned treatment. Doctors stopped prescribing it. Years later, we learned the data had been misinterpreted, but the damage was already done.

The study鈥攐ne arm of the Women鈥檚 Health Initiative (WHI), a massive trial on disease prevention in aging women鈥攚as never meant to serve as the final word on hormone replacement therapy, or even examine whether it was safe and effective for menopause symptoms like , , , or .

shows that for most women in menopause, the outweigh the cons, and leading experts are pushing to make this widely known. In 2025 the to discuss the latest evidence on HRT, with leading researchers and clinicians calling for changes rooted in the latest science.

Yet the legacy and flaws of the persist in prescribing patterns, medical education, and the options women are (or aren鈥檛) offered to treat .

spoke with doctors who practiced before and after the WHI to unpack what the study actually showed, its flaws and how the message got distorted, and what it will take to finally move menopause care forward.

Early 1990s: Hormone Therapy Is Considered Essential

In 1991, the National Institutes of Health began recruiting for the Women鈥檚 Health Initiative (WHI), a $625 million, long-term, randomized controlled study to investigate ways to prevent the leading causes of and disability in postmenopausal women.

In total, 161,808 postmenopausal women aged 50 to 79 were recruited for the study; 68,132 participated in one of three clinical trial arms: hormone therapy, , or calcium and vitamin D supplementation.

The hormone therapy trial was intended to last nine years to evaluate the long-term health impacts of the two most common HRT regimens at the time: conjugated equine estrogen (CEE) plus progestin () for women with a uterus, and CEE alone for those who鈥檇 had a hysterectomy and no longer had a uterus.

鈥淲e were taught hormones were the greatest thing since sliced bread. They protected women鈥檚 hearts, brains, and bones, and therefore we wanted all menopausal women to be on hormone replacement therapy,鈥 says Deb Matthew, M.D., board-certified integrative medicine physician and author of 鈥淭his Is Not Normal: A Busy Woman鈥檚 Guide to Symptoms of Hormone Imbalance.鈥

July 2002: WHI Headlines Change Care Overnight

On July 9, 2002, the NIH held a press conference, announcing it was stopping the estrogen-plus-progestin arm of the trial early, citing increased rates of blood clots, , , and breast cancer in women taking the combined hormone therapy.

鈥淓verybody flushed their hormones down the toilet. Patients didn鈥檛 want to take them. Doctors stopped prescribing them. Literally overnight, it just sort of stopped,鈥 says New York City鈥揵ased OB-GYN Alyssa Dweck, M.D.

While the HRT study had also shown benefits鈥攏otably, fewer hip fractures and cases of colorectal cancer鈥攖hose findings were largely drowned out by the news headlines, which rapidly spread an alarming message: Hormone therapy was dangerous.

Clinicians were blindsided.

Typically, trial data is shared with physicians in advance, giving them time to review the findings and prepare for treatment changes and patient questions. In this case, the WHI study wasn鈥檛 published in JAMA until July 17, more than a week after the press conference.

鈥淲e had no idea that the study was even released,鈥 says Tara Scott, M.D., a board-certified OB-GYN, and Menopause Society-certified menopause practitioner.

鈥淧hones were ringing off the hook with people frantic, not knowing how to stop their hormones,鈥 says Robin Noble, M.D., also an OB-GYN and Menopause Society-certified provider.

Doctors were horrified that they鈥檇 been regularly prescribing a treatment that now appeared to increase the risk of breast cancer, and took women off hormones.

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Data from WHI study on risks of combined hormone therapy.
Hone Health


鈥淥n the first day of medical school, literally the first thing that we do is take the Hippocratic oath,鈥 Matthew says. 鈥淎nd part of that oath says, 鈥楩irst, do no harm.鈥 So doctors would rather do nothing and allow harm to come to you than to do something that ultimately causes you to have harm.鈥

The 2000s: A Generation of Providers Is Trained to Avoid Hormones

Before the WHI findings were released, around were taking hormones to manage symptoms. Within months of the press conference, that .

Menopause training itself, already underemphasized in medical education, also dwindled to virtually nothing. 鈥淭hose who did their medical school and residency in the 2000s really had very little training on menopause and menopausal care,鈥 Noble says.

鈥淚n residency, I saw patients who would tell me, 鈥楾his menopause thing is kicking my ass. I . I have . I鈥檓 ,鈥欌 says board-certified OB-GYN and integrative medicine physician Jennifer Roelands, M.D. 鈥淚 was instructed that it鈥檚 just a , and they just have to , , and that鈥檚 just what happens.鈥

What made that retreat even more damaging: the breast cancer risk that HRT drove was small and poorly reported by the media.

The actual increase in breast cancer risk for women on the combination therapy was small鈥攋ust one additional case per 1,000 women.

鈥淭hey called it a 26 percent increase in the risk of breast cancer because it went from four to five,鈥 says Matthew. 鈥淚t got overblown to be a big risk, when in fact it was a teeny, tiny risk.鈥

That single statistic about breast cancer in the Women鈥檚 Health Initiative study, divorced from its absolute context, shaped care for decades.

Meanwhile, other benefits of HRT reported in the WHI went unreported: Women who received estrogen alone actually had a reduction in the risk for breast cancer. But that part of the WHI study was still ongoing, and by the time it ended in 2004, distrust of HRT had already calcified.

2010s: The Hidden Toll of HRT Avoidance Emerges

As it turns out, not taking HRT had significant effects on many women鈥檚 health.

A estimated that between 2002 and 2012, as many as 91,000 postmenopausal women in the U.S. died prematurely from conditions that HRT might have helped prevent. 鈥淸Estrogen therapy] in younger postmenopausal women is associated with a decisive reduction in all-cause mortality,鈥 the study authors wrote.

鈥淲omen were literally better off and lived longer on the hormone replacement therapy than they were without hormone replacement therapy, even with the tiny increase in the risk for breast cancer,鈥 says Deb Matthew, M.D. 鈥淭hat information never really made it out to the public and never really made it out to doctors.鈥

A emphasized another flaw with the WHI study trials: the age of the participants. The average participant in the hormone trial was 63, more than a decade past the typical age of menopause onset, which is 51. This matters because both influence hormone therapy鈥檚 risks and benefits.

The WHI study also deliberately enrolled older, asymptomatic women to maintain the integrity of its double-blind, placebo-controlled design. Including women with vasomotor symptoms like would have unblinded the trial, as those on placebo would continue experiencing symptoms while those on hormones would likely feel relief. But studying menopause in an older population also meant studying women who were already at higher baseline risk for cardiovascular disease and cancer, regardless of hormone use.

Today: Hormone Therapy Evolves and Gains Traction

Two decades after the WHI fallout, the cultural conversation around menopause started to shift. Celebrities like Naomi Watts, Gwyneth Paltrow, Drew Barrymore, Halle Berry, Salma Hayek, and Oprah Winfrey started speaking candidly about their experiences with perimenopause and menopause.

鈥淎 lot of really influential women who are power brokers in the media, in Hollywood, and in business were just unwilling, and rightfully unwilling, to suffer with symptoms,鈥 Dweck says.

On social media, OB-GYN influencers like Mary Claire Haver, M.D., and Jen Gunter, M.D., have built large followings by spreading information and opinions about menopause. 鈥淭hat really drove a lot of patients to go, 鈥楬uh, I don鈥檛 actually have to suffer,鈥欌 Roelands says.

In recent years, the term 鈥溾 (MHT) has gained traction to distinguish it from other types of hormonal therapy, but also to 鈥渞ebrand鈥 HRT and shift the therapy away from any negative connotations that still linger after the WHI study.

And education is starting to spread that today鈥檚 hormone regimens rely more on and , which have been found to be much safer than the hormones used in the study.

A published in Menopause: The Journal of the North American Menopause Society stated: 鈥淭he best available evidence indicates that the use of 鈥 does not elevate breast cancer risk to the same degree, if at all, and are safer with respect to risk of breast cancer.鈥 Other post-WHI research from 2013 and 2022 found transdermal HRT did not increase the risk of blood clots as oral HRT does.

Gaps Between Science and Practice Remain

Still, greater visibility hasn鈥檛 necessarily translated into more women using hormones. estimated only about 5 percent of women in 2020 were taking HRT to manage their menopause symptoms, down from 27 percent in 1999.

鈥淓ven with this newer information that鈥檚 come out with WHI data, the hasn鈥檛 really increased all that much,鈥 Dweck says. 鈥淚t is taking a while for people to get the message that for many it鈥檚 safe and very effective.鈥

That 鈥減eople鈥 includes physicians. There are too few physicians steeped in menopause care, Scott says. 鈥淭here aren鈥檛 enough providers,鈥 she says. 鈥淚 think there are at most 4,000 certified menopause practitioners, and they鈥檙e not in every state.鈥

A of 12 studies on medical menopause education found some sobering statistics.

  • More than 90 percent of medical residents said they felt unprepared to deal with patients experiencing menopause.
  • One in five family medicine residents received no menopause education
  • Less than 7 percent feel adequately prepared to treat menopause.
  • Almost half of those residents had not received menopause management training or were unfamiliar with it.
  • A full 67 percent said they did not adequately understand HRT.

That lack of clinical knowledge trickles down to patients. Many women still fear breast cancer; others favor over pharmaceutical treatments, notes Dweck.

Experts call for policy change

With rising public awareness, growing research, and a new generation of vocal advocates, momentum has been building to address menopause care. That movement reached a milestone in July 2025, when the FDA convened an expert panel to discuss hormone therapy. Leading researchers and clinicians urged regulators to finally align policy with the best available science and to move past the shadow cast by the WHI.

Multiple experts called on the FDA to remove its current black box warning on . JoAnn Pinkerton, M.D., the past president and emeritus executive director of The Menopause Society, noted that the WHI data never supported a link between and risks like breast cancer or stroke.

Other experts proposed increasing . Mary Jane Minkin, M.D., a clinical professor of obstetrics, gynecology, and reproductive sciences at Yale University School of Medicine, called for renewed curriculum standards to help OB-GYNs, nurse practitioners, and physician assistants understand the nuances of hormone therapy and symptom care.

Reframing The Study That Redefined Menopause Care

Despite the fallout and its potential flaws, experts agree the WHI remains a landmark study.

鈥淭he WHI was the largest and most comprehensive clinical trial ever performed on women anywhere in the world,鈥 says Nanette Santoro, M.D., a professor in the Department of Obstetrics and Gynecology at the University of Colorado School of Medicine. 鈥淚t鈥檚 the standard that other trials should be measured against. It was run by experts, the processes and procedures were state-of-the-art for its time, and its results are robust and have been reinforced by the lengthy follow-up of women after they stopped the treatment.鈥

But, Santoro adds, the WHI study is just like any other clinical trial: 鈥淚t can tell you about one treatment at one point in time on one population.鈥

The real lesson of the WHI study isn鈥檛 to avoid hormones or to embrace them blindly. It鈥檚 that women deserve informed, individualized menopause care that reflects evolving science, by educated practitioners.

鈥淲e need to meet people where they are,鈥 says Noble, 鈥渁nd where they want to be.鈥

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