HRT and Menopause: What Have We Learned Since the Women’s Health Initiative?

Why Are Many Women Still Frightened of HRT?

If you have ever been told that “HRT causes breast cancer”, you are certainly not alone.

Much of the fear surrounding menopause hormone therapy can be traced back to 2002, when early results from the Women's Health Initiative (WHI) were released.

The WHI was an enormous and important research program investigating ways to improve the health of women as they aged. However, the way its initial hormone therapy findings were communicated created a message that was much simpler — and considerably more frightening — than the science itself.

Headlines around the world effectively told women:

HRT causes breast cancer.

Prescribing dropped dramatically, and millions of women stopped hormone therapy. More than two decades later, we have a much better understanding of what the WHI actually showed.

The First Important Distinction: Not All HRT Is the Same

One of the biggest problems with the original conversation around the WHI was that “HRT” was treated as though it were one single treatment.

It isn't.

The WHI included different treatment groups, including:

• oestrogen alone, for women who had previously had a hysterectomy
• oestrogen plus a synthetic progestogen, for women who still had their uterus

These treatments produced different breast cancer outcomes.

That distinction matters enormously.

What Happened in 2002?

On 28 June 2002, the combined oestrogen-plus-progestogen arm of the WHI was stopped early.

A press release announced an apparent 26% increase in breast cancer risk and a “lack of overall benefit.”

The announcement rapidly became international news and profoundly changed the way doctors and women viewed hormone therapy.

However, subsequent analysis and discussion of the WHI data have demonstrated that the original message lacked important context and nuance.

Most importantly:

The breast cancer findings for oestrogen alone were not the same as those for combined hormone therapy.

What Did the Oestrogen-Only WHI Trial Actually Find?

Long-term follow-up of women in the WHI who had undergone hysterectomy and were randomised to oestrogen alone produced a very different picture from the one many women still associate with HRT.

Dr Devaki Lindsey Berkson has spent many years drawing attention to this distinction and to subsequent analyses of the WHI data.

In long-term WHI follow-up, women randomised to oestrogen alone experienced:

↓ Breast cancer incidence

and

↓ Breast cancer mortality

compared with women receiving placebo.

This is very different from simply saying: “Oestrogen causes breast cancer.” The evidence does not support such a blanket statement.

Relative Risk Can Sound Much Scarier Than Absolute Risk

Another important lesson from the WHI is the way medical risk is communicated.

A headline such as: “26% increased risk” sounds enormous.

But percentages like this often describe relative risk, rather than telling us how many additional women were actually affected.

When discussing HRT — or any medication — I prefer to look at:

What is the actual change in risk for this individual woman?

Your baseline risk matters. So do your age, health, family history, type of hormone, dose, route of administration and length of treatment.

Oestrogen Does Much More Than Control Hot Flushes

Oestrogen receptors are found throughout the female body. This helps explain why falling oestrogen levels can affect much more than periods and temperature regulation.

Oestrogen has important physiological effects involving the:

1. Brain 
   • Oestrogen interacts with areas involved in memory, cognition, mood and neuronal function.
2. Bones
   • Oestrogen helps maintain bone density and reduces bone loss after menopause. Menopausal hormone therapy has been shown to reduce fracture risk.
3. Cardiovascular System
   • Oestrogen influences blood vessels, lipid metabolism and other aspects of cardiovascular physiology.
4. Muscles and Connective Tissue
   • The menopausal transition can affect muscle, joints, tendons and overall musculoskeletal health.
5. Metabolism
   • Hormonal changes interact with insulin sensitivity, body composition and metabolic health.
6. Genitourinary Tissues
   • Oestrogen supports the tissues of the vagina, vulva, bladder and urinary tract. This is why menopause is not simply about stopping periods. It represents a significant physiological transition affecting many systems throughout the body.

It represents a significant physiological transition affecting many systems throughout the body.

What About The Brain?

This is an exciting area of research, but also one where we need to avoid making promises that the evidence cannot yet support.

Oestrogen receptors are abundant within areas of the brain involved in memory and cognition, including the hippocampus.

Research has investigated associations between menopausal hormone therapy, hippocampal structure, cognition and later neurodegenerative disease. Some observational studies have reported lower rates of Alzheimer's disease among hormone therapy users, while smaller imaging studies have demonstrated changes in hippocampal grey-matter volume following estradiol treatment.

This does not mean that HRT is currently prescribed as a treatment or guaranteed prevention for dementia.

It does tell us that the relationship between oestrogen and the ageing brain is considerably more complex than we once appreciated.

What About Our Bones?

Here the evidence is much clearer. Oestrogen deficiency accelerates bone loss after menopause.

Menopausal hormone therapy:

• reduces bone loss
• helps preserve bone mineral density
• reduces vertebral and non-vertebral fractures
• reduces hip fracture risk

The WHI and subsequent research have provided strong evidence for the protective effects of menopausal hormone therapy on bone.

For some women, protecting their future bone health is an important part of the conversation about HRT — not merely controlling hot flushes.

What About Starting HRT After 60?

You may have heard:

“If you didn't start HRT within 10 years of menopause, you've missed your chance.”

Again, the reality is more nuanced.

For most healthy women experiencing symptoms who are under 60 or within approximately 10 years of menopause, the benefit-risk profile of appropriately prescribed menopause hormone therapy is generally considered favourable.

Starting systemic HRT later requires more individualised assessment.

That does not automatically mean that every woman over 60 — or every woman more than 10 years beyond menopause — can never use hormone therapy.

It means we need to consider her individual circumstances, including cardiovascular health, thrombotic risk, breast history, bone health, symptoms and the formulation and route of hormone therapy being considered.

Age alone shouldn't replace an individual clinical assessment.

What If I Have Had Breast Cancer?

This deserves a very important distinction.

There is fascinating and evolving research examining hormone therapy after breast cancer, and Dr Berkson discusses this literature extensively. She highlights studies reporting reassuring outcomes as well as limitations in some of the research traditionally used to discourage hormone therapy after breast cancer.

However, a previous breast cancer diagnosis requires specialist, individualised discussion.

Systemic menopausal hormone therapy is not routinely recommended for women with a history of hormone-sensitive breast cancer, and the evidence remains complex.

For women experiencing significant menopausal symptoms after breast cancer, management should consider:

• the type and stage of the original cancer
• hormone-receptor status
• current endocrine treatment
• recurrence risk
• severity of menopausal symptoms
• bone, cardiovascular, sexual and genitourinary health
• non-hormonal treatment options
• and the woman's own values and preferences.

This is an area where shared decision-making is essential.

Is HRT safe?

There isn't a universal yes-or-no answer.

A better question is:

“What are the potential benefits and risks of HRT for me?”

Modern menopause care should be personalised. We consider:

• your age and stage of menopause
• your symptoms
• whether you have a uterus
• personal and family medical history
• breast health
• cardiovascular and metabolic health
• bone health
• migraine and clotting history
• medications
• the hormone being prescribed
• its dose
• and how it is delivered

For many appropriately selected women, menopause hormone therapy can provide substantial benefits with a favourable benefit-risk profile. For others, different approaches may be more appropriate.

The Most Important Message

The legacy of the 2002 WHI announcement is still influencing women's decisions today. But our understanding has moved on.

Oestrogen is not simply a “breast cancer hormone.” HRT is not one single medication.

Oestrogen-alone and oestrogen-plus-progestogen therapy should not be assumed to have identical risks. Route, formulation, dose, timing and the individual woman all matter. And decisions about menopause treatment should be based on current evidence not frightening headlines from more than 20 years ago.

If fear about breast cancer has been the main reason you have avoided discussing hormone therapy, it may be worth having that conversation again.

You deserve an individual assessment of your benefits and risks, rather than a blanket yes or no.

You Deserve Clear, Individualised Menopause Care

Menopause hormone therapy is a deeply personal decision, and understanding your options is an important part of feeling confident about your care.

If you're considering HRT, have been told conflicting information, or simply want to understand whether it may be appropriate for you, a personalised consultation can help you explore the potential benefits and risks in the context of your own health.

You don't have to make that decision based on fear or outdated headlines.

Book a consultation with My Menopause Clinic Australia and let's look at the whole picture together.

Acknowledgement

This patient resource was inspired by and adapted from the work of Dr Devaki Lindsey Berkson, particularly her August 2026 article The Estrogen “Lie” That Changed Women's Medicine: How a “Press Release” Reshaped Hormone Therapy for Generations.

Dr Berkson has written and lectured extensively about hormone physiology, the Women's Health Initiative and the historical interpretation of menopause hormone therapy.

The original article contains an extensive scientific reference list, including WHI publications and research examining breast cancer, cognition, bone health, cardiovascular health and healthy ageing.

Selected Reading

• Women's Health Initiative hormone therapy trials and long-term follow-up
• Menopausal Hormone Therapy and Long-term All-Cause and Cause-Specific Mortality — JAMA, 2017
• 'Tis But a Scratch: A Critical Review of the Women's Health Initiative Evidence Associating Menopause Hormone Therapy with the Risk of Breast Cancer — Menopause, 2023
• Use of Menopausal Hormone Therapy Beyond Age 65 Years and Its Effects on Women's Health Outcomes by Types, Routes, and Doses — Menopause, 2024
• Berkson DL. Safe Hormones, Smart Women. Awakened Medicine Press, 2010.

A Note for My Patients

This information is for education and should never replace individual medical advice.

Hormone therapy needs to be considered in the context of your own medical history, symptoms, risks, goals and preferences.

That is exactly why our consultations are individualised.