Few areas of medicine have been as distorted in public understanding as hormone replacement therapy. A generation of women avoided it on the basis of a headline, and a generation of doctors became reluctant to offer it. Unpicking that requires going back to what happened.
What happened in 2002
The Women's Health Initiative was a large randomised trial of HRT. In 2002 one arm was halted early and reported an increased risk of breast cancer and cardiovascular events. Coverage was immediate and severe; HRT prescribing fell off a cliff worldwide.
Subsequent reanalysis identified problems with how those results were being generalised. The average participant was 63 — more than a decade past menopause. Many were older still. The formulation used, conjugated equine oestrogens with medroxyprogesterone acetate, is not what is typically prescribed in the UK now. And the absolute risks were considerably smaller than the relative-risk headlines implied.
Where the evidence sits now
NICE guidance is clear that for most women with troublesome menopausal symptoms starting HRT near menopause, benefits outweigh risks. Specifics matter more than the headline.
| Consideration | What the evidence indicates |
|---|---|
| Vasomotor symptoms | HRT is the most effective treatment available. Nothing else comes close. |
| Bone density | Reduces fracture risk while taken. |
| Oestrogen-only HRT (after hysterectomy) | Little or no increase in breast cancer risk. |
| Combined HRT | A small increase in breast cancer risk, related to duration of use, which falls after stopping. |
| Route of oestrogen | Transdermal — patches and gels — does not carry the small clot risk associated with oral oestrogen. |
| Cardiovascular | No increased risk when started under 60. Possible benefit when started early. |
| Vaginal oestrogen | Very low systemic absorption. Considered separately, and appropriate for many women who cannot take systemic HRT. |
For perspective on the breast cancer figure: NICE puts the additional cases from five years of combined HRT in women aged 50–59 at roughly 5 per 1,000. Drinking two or more units of alcohol daily, or being significantly overweight, carries a comparable or larger effect. That comparison is not a reason to dismiss the risk — it is a reason to size it correctly.
The types
- Oestrogen — patch, gel, spray or tablet. Transdermal avoids the first-pass liver effect and the associated clot risk.
- Progestogen — required alongside oestrogen for anyone with a uterus, to protect the womb lining. Available as tablets, as part of a patch, or via a hormonal coil.
- Body-identical — micronised progesterone and 17β-oestradiol, structurally identical to what the body makes, regulated and available on the NHS. Not the same as compounded 'bioidentical' preparations, which are unregulated and not recommended.
Who should be cautious
HRT is not for everyone. A personal history of breast cancer, an oestrogen-dependent cancer, unexplained vaginal bleeding, untreated endometrial hyperplasia, active liver disease or a history of clotting disorders all need specialist input. Family history matters but rarely rules HRT out on its own.
If your GP is hesitant and your symptoms are significant, it is reasonable to ask for a referral to a menopause specialist. The British Menopause Society maintains a directory.
Sources
NICE NG23: Menopause — diagnosis and management
Benefit-risk framing, absolute risk figures, route-specific clot risk, and guidance against compounded bioidentical hormones.
Women's Health Initiative, 2002 and subsequent reanalyses
Original findings and the age-at-initiation reanalysis that reframed them.
British Menopause Society consensus statements
Current UK practice on HRT formulation, route and duration.
