Why two doctors can give you opposite advice about HRT

Medically reviewed by

Dr. William Declerck

Physician

22 October 2026

Hormones & treatment Finding your way in care

In short

Seven guideline bodies write about hormone therapy for menopause. They agree on less than you would expect.
A 2024 review assessed nine menopause hormone therapy guidelines. Of more than 300 recommendations, only 17 appeared consistently in at least two of them. [8]
The clearest example is how long you can stay on treatment. Dutch guidance says aim for under five years. [5][6] The International Menopause Society says there is no reason to set a limit. [7] NICE declines to name any duration at all. [1]
Inside Belgium, two sources say there is no fixed limit [2][3] and a third says it is never appropriate to continue treatment after 65. [4]
They also disagree about whether hormone therapy helps brain fog, and about whether the type of progestogen changes your risk.
None of this means your doctor is wrong. It means the evidence leaves real room for judgement, and you are entitled to hear the reasoning behind the advice you are given.

Two doctors, two answers

You have been on hormone therapy for four years. Your symptoms are controlled. You ask whether you can continue.

If your doctor works from the Dutch GP standard, you will hear that the aim is to stay under five years, because risks accumulate gradually. [5]

If your doctor works from the International Menopause Society recommendations published in 2026, you will hear that there is no reason to place a limit on duration, and that the real question is whether treatment is still doing what you wanted it to do. [7]

Both answers are defensible. Both are written down in current guidance. Neither doctor is out of date.

That is not a story about two unusual doctors. In 2024 a team assessed nine menopause hormone therapy guidelines against a standard quality instrument. They extracted more than 300 recommendations. Only 17 of them appeared consistently in at least two guidelines. [8]

A grid of about 300 dots, one for each recommendation, with 17 highlighted in orange. A 2024 review of nine menopause hormone therapy guidelines found that only 17 of more than 300 recommendations appeared consistently in at least two of them. — Only 17 of more than 300 recommendations were consistent across at least two guidelines. The nine guidelines reviewed are not the seven compared here (Roman et al., 2024).

This page sets out where the major guidelines differ and why. It is written for women who want to understand their own care. It is also written so that you can see what your doctor is looking at, because the two things are the same problem viewed from either side of the desk.

Who the seven are

NICE (UK). Widely quoted everywhere, including in Belgium and the Netherlands. [1]
BMS, the Belgian Menopause Society. The specialist society. [2]
RIZIV-INAMI. The Belgian national consensus, reached by a jury in 2024. [3]
BCFI. The independent Belgian drug bulletin, which most Belgian GPs read. [4]
NHG. The Dutch GP standard, which is what a Dutch huisarts works from. [5]
NVOG and the Dutch Menopause Society. The Dutch specialist track. [6]
IMS, the International Menopause Society. Rewritten in 2026 for the first time in a decade. [7]

A note on words before we start

Three terms come up throughout, and they are worth having in plain language.

Oestrogen is the hormone that falls during menopause and causes most of the symptoms. Progestogen is a second hormone given alongside it if you still have a womb, to protect the womb lining. Almost every disagreement below is about one of those two: which form, which route, for how long.

Transdermal means through the skin, as a patch, gel or spray, rather than swallowed as a tablet. This turns out to matter more than it sounds.

Bio-identical means a hormone with the same molecular structure as the one your body makes, produced to pharmaceutical standard and licensed as a medicine. It is not the same as compounded bio-identical hormones, which are mixed to order by a compounding pharmacy, often marketed as more natural, and are not licensed or quality-controlled. On this the guidelines do not disagree at all. NICE states plainly that the efficacy and safety of unregulated hormone preparations are unknown. [1] Where this article says bio-identical, it means the licensed kind.

The most common questions we get

Do all doctors follow the same menopause guideline? It is a reasonable thing to assume, and it is not the case. A Belgian GP is most likely to work from BCFI and the RIZIV consensus. A Dutch GP works from the NHG standard. Specialists in both countries work from their menopause societies. Any of them may also read NICE or the International Menopause Society.

Does that mean the guidelines are unreliable? If you have just learned this, it is unsettling, and the honest answer is more reassuring than it first sounds. Where good trial data exist, the guidelines agree closely. Where the data are thin, they diverge, because each body has to decide how cautious to be with uncertainty. That is a judgement, and reasonable people make it differently.

How different can the advice actually be? On some questions, different enough to change what happens to you. On duration of treatment, two Belgian sources say there is no fixed limit and a third says never past 65.

What am I supposed to do with this? Nobody expects you to arbitrate between guideline committees. What this gives you is one useful question: which guidance is my doctor working from, and why that one. A doctor who can answer that is giving you a considered position rather than a default.

What is genuinely settled

Guideline disagreement makes better reading than guideline agreement, so it is worth being precise about how much is actually common ground. Two things are agreed by all seven bodies.

Hormone therapy works for hot flushes and night sweats. None of the seven disputes this. They word it with different strength: NICE says offer it [1], the International Menopause Society and three others call it the most effective treatment available [2][3][4][7], and the Dutch GP standard says consider it, putting the effect at roughly eight fewer flushes a day, against five fewer on placebo. [5] The direction is the same everywhere.

You do not need a blood test to diagnose menopause over 45. Six of the seven say so directly, and the seventh does not discuss diagnosis at all. [1][3][5][6][7] The Belgian Menopause Society ties its version to twelve months without a period rather than to symptoms alone. [2]

Beyond those two, agreement is partial. Most bodies prefer oestrogen through the skin where clot risk is raised, but the Dutch GP standard declines to state a preference, judging the evidence too weak. [5] Most say local vaginal oestrogen is considered differently from treatment acting throughout the body, but again the Dutch GP standard treats the cautions as the same. [3][5] Even the number of days a month you need a progestogen is not settled. It is twelve in Belgian and Dutch specialist guidance [3][4][6], fourteen in the Dutch GP standard [5], ten or twelve depending on which molecule in the international recommendations [7], and unstated by NICE and the Belgian Menopause Society.

That last one is a small detail with a large lesson. If seven expert bodies cannot agree on how many days a month a tablet should be taken, the disagreements that follow should not be surprising.

Where the guidelines differ

How long can you stay on HRT?

This has the widest reach, because it affects everyone who is already doing well on treatment.

The Dutch GP standard states the aim plainly: aim for use under five years, because the risks rise gradually. [5] Dutch specialist guidance lands in the same place, with as short as possible, preferably under five years. [6]

NICE takes a different approach and says so, recording that it is impossible to recommend one specific duration because it depends on too many factors. [1] Declining to name a number is not the same as saying no limit applies, and NICE stresses that duration is rediscussed at every review.

The International Menopause Society is blunter: "There are no reasons to place mandatory limitations on the duration of MHT." [7]

Belgium holds both positions at once, and by two to one. The Belgian Menopause Society writes that there is no arbitrary limit on the duration of treatment. [2] The RIZIV consensus jury agrees, stating that there is no scientific evidence treatment must be stopped at any point, whether after a given duration or from a given age. [3] BCFI, the independent Belgian drug bulletin, disagrees with both: "Het is nooit aangewezen om de behandeling voort te zetten na de leeftijd van 65 jaar", it is never appropriate to continue treatment after the age of 65. [4]

A line from more restrictive to less restrictive showing four positions on how long hormone therapy can continue. BCFI (Belgium) says it is never appropriate to continue after 65. NHG and NVOG/DMS (Netherlands) aim for under five years. NICE (UK) declines to name a duration. BMS and RIZIV (Belgium) and IMS (international) set no fixed limit. — How long hormone therapy can continue, according to seven guideline bodies. Two Belgian sources reject a fixed limit; the third says never continue after 65.

If you have been told you must stop at five years, that is a real position held by real guidelines, and it is not the only one. The useful thing to ask is whether the five years is a rule your doctor is applying, or a point at which they want to reassess with you. Those are different conversations, and the second one is what most guidelines are actually describing.

Does it help brain fog?

Losing words mid-sentence is one of the most frightening parts of perimenopause, and it is where the guidelines are least useful, for a reason worth understanding.

Three of the seven address brain fog directly, and they do not agree.

BCFI groups it with the other psychological and cognitive symptoms of perimenopause: mood changes, disturbed sleep, problems with concentration and memory, and the sensation Dutch calls hersenmist. Its conclusion is that the evidence for hormone therapy in these symptoms is currently limited. [4]

The RIZIV consensus names brain fog among the more complex symptoms of menopause, alongside low mood, sleep problems and sexual function. It writes that these have been studied less, and that hormone therapy appears to have less or even no effect on them. On mood specifically, RIZIV does not recommend hormone therapy for mood complaints, while noting that oestrogens could have a favourable effect on depressive symptoms. [3]

The Belgian Menopause Society names brain fog too, and a call-out box in its 2026 guidance recommends hormone therapy for it. The body text of the same document says hormone therapy also improves mental and cognitive complaints, brain fog among them, but that these are currently not a reason to start treatment and not an official indication for it. [2] Different positions are taken within the same organisation.

The other four either answer adjacent questions or say nothing about it. NICE and the Dutch specialist guidance do not address brain fog. The International Menopause Society's statement, at its highest evidence grade, is about cognitive decline: the dementia end of the spectrum rather than the transient fog of perimenopause. [7] The Dutch GP standard addresses mood, and says hormone therapy probably has little or no effect on it. [5] Those are real findings about real questions. Neither is a finding about brain fog.

So the picture is narrower than it first looks. Three Belgian sources examine brain fog directly. Two are cautious about hormone therapy for it, and the third recommends it in a call-out while its body text stops short of an indication. Everyone else is talking about something adjacent to it.

None of that makes the symptom imaginary. It is real, it is recognised, and it is common. What it means is that the evidence base here is thinner than for hot flushes, and that a doctor who says so is being accurate rather than dismissive. You can read more about what these symptoms look like on our page about brain fog.

What are the actual numbers?

Most guidelines describe breast cancer risk in words rather than figures. NICE gives no absolute numbers in the guideline itself and points clinicians to a separate discussion aid. [1] The International Menopause Society gives none for breast cancer. [7] The Belgian Menopause Society gives none. [2]

Two sources do publish figures, and they are worth reading slowly, because they are not measuring the same thing.

The RIZIV consensus states four extra cases per 1,000 women after five years of treatment. RIZIV adds its own comparison, that this is smaller than the increase caused by smoking ten cigarettes a day, by alcohol, or by obesity. [3]

The Dutch GP standard works over three years. Against a background of nine breast cancers per 1,000 women aged 45 to 64, it puts oestrogen alone at a relative risk of 1.2, oestrogen with dydrogesterone at 1.0, and oestrogen with progesterone at 0.9. [5]

A relative risk of 1.0 means no change from the background rate. 1.2 means a fifth higher, which against nine cases per 1,000 works out at roughly two more.

Those two sets of numbers cannot be laid side by side. Different time horizons, different treatment combinations, different baseline populations. What they jointly show is that the figures are small, and that they vary by what you take and for how long.

Look again at the Dutch figures and one pattern stands out. The two regimens showing no increase both use a bio-identical or near-bio-identical progestogen. That distinction, between bio-identical and synthetic hormones, does more work than almost anything else on this page, and it is the subject of the next section.

A grid of 1,000 dots, each a woman aged 45 to 64 followed for three years. Nine dark dots are the breast cancers expected without hormone therapy and two orange dots are the extra cases with oestrogen alone. Below, four tiles: no hormone therapy 9 per 1,000; oestrogen alone 11 (relative risk 1.2); oestrogen with dydrogesterone 9 (relative risk 1.0); oestrogen with progesterone 8 (relative risk 0.9, range 0.7 to 1.2, which crosses 1.0 and so shows no real reduction). — Breast cancer over three years per 1,000 women aged 45 to 64, by regimen. NHG figures; not comparable with RIZIV’s five-year figure.

Does the type of progestogen matter?

If you take oestrogen and still have a womb, you also take a progestogen. There are several kinds, and the guidelines disagree about whether the choice changes your risk.

Two of them are bio-identical or close to it: micronised progesterone, and dydrogesterone. The others are synthetic.

The International Menopause Society states that breast cancer risk appears lower with micronised progesterone or dydrogesterone than with a synthetic progestogen, then hedges in the very next line, saying there are not enough data to fully evaluate the differences. [7] The Belgian Menopause Society and the RIZIV consensus both prefer the same two molecules. [2][3] Dutch guidance prefers them as well, and the Dutch GP standard ranks dydrogesterone first. [5][6]

NICE examined the same question and declined to answer it, recording that there is insufficient evidence to establish whether risk differs, and issuing a research recommendation instead. [1] BCFI reaches NICE's conclusion rather than the one its own national consensus jury reached: there are insufficient data to confirm that any type of oestrogen or progestogen is safer. [4]

In practice this matters less than it sounds, because every body that states a preference names the same two molecules. What differs is how confidently the preference is stated.

A table comparing seven guideline bodies on five questions: duration of treatment, type of progestogen, cognitive symptoms, testing over 45 and route of oestrogen. The full contents are listed in the legend. — Where seven guideline bodies stand on five questions. NICE and NVOG/DMS say nothing about cognitive symptoms.

What changed in November 2025, and how it was reported

In November 2025 the American regulator removed the boxed warning from hormone therapy labels, the warning that had linked it to cardiovascular risk, breast cancer and dementia. [9] The primary source for that decision is a viewpoint in JAMA written by the regulator's own leadership, not a systematic review of the evidence. The Belgian Menopause Society sets this out in the introduction to its 2026 guidance. [2] The International Menopause Society records it too. [7]

The Belgian Menopause Society describes the regulator's reasoning as accumulated evidence showing a generally favourable balance for women under 60, or within ten years of the start of menopause, particularly for hot flushes and night sweats and for prevention of bone loss. [2]

Two things are worth adding, because the story was widely oversimplified.

The International Menopause Society describes the change as removing the boxed warning in favour of more nuanced labelling tailored to each product's form and indications. It also warns that the announcement was over-read. Some online advocates treated it as an unequivocal win, while experts in women's health pointed to evidence gaps and to misalignment with medical guidelines in the announcement and the coverage that followed. [7]

And the cautious sources could not have taken it into account. BCFI was published in January 2025 and the Dutch GP standard in 2022. [4][5] Their caution is not a response to the label change, because it predates it.

A timeline of when each guideline was written. NHG in June 2022, the RIZIV-INAMI consensus in May 2024, the NICE NG23 evidence update in November 2024 (amended since, most recently April 2026), BCFI Folia in January 2025 and the NVOG/DMS handbook in 2025 were all written before the FDA removed the boxed warning in November 2025. The BMS guidelines of January 2026 and the IMS recommendations of 2026 could take it into account. — When each guideline was written, relative to the FDA label change of November 2025.

This still matters, for a specific reason. Much of the fear women carry about hormone therapy traces back to one study reported in 2002 and to the warnings that followed. Those warnings shaped a generation of conversations in consulting rooms. The label has now changed, and the change is real, even if much of the coverage carried more certainty than the evidence behind it.

If you are a clinician reading this

The short version. Duration is the sharpest divergence: NHG and NVOG both target under five years [5][6], BMS and the RIZIV jury reject a fixed limit [2][3], BCFI stops at 65 [4], IMS rejects mandatory limits [7], and NICE declines to name one [1]. Progestogen preference splits along the same line, with everyone except NICE and BCFI stating one. On cognitive decline, a separate question from brain fog, IMS carries the strongest statement in the set, at its highest grade: except in premature ovarian insufficiency or early menopause, hormone therapy is not recommended to prevent or treat cognitive decline at any age. [7]

Every claim on this page is sourced to a numbered guideline below, and the quotations are verbatim from the published documents rather than from summaries.

So which doctor was right?

Neither of them was wrong, which is a less satisfying answer and a more useful one.

One was working from guidance that treats five years as the point where the balance should be reassessed. The other was working from guidance that treats duration as an open question, answered by how you are actually doing. Both were reading real evidence. They weighed the uncertainty differently, because the evidence leaves room to.

Knowing that changes what you can ask for. Not a second opinion, necessarily, but the reasoning behind the first one.

Four questions are worth taking to your next appointment.

Which guidance are you working from on this, and why that one.

If there is a time limit on my treatment, where does it come from.

Where this differs from other guidance, what makes you comfortable with the position you are taking.

And what changes if I take bio-identical hormones only, with the oestrogen applied through the skin rather than swallowed.

A doctor who welcomes those questions has thought about the answers.

If you are not yet sure whether what you are experiencing is perimenopause, the symptom checker takes a few minutes and gives you something concrete to bring to that conversation.

If you would rather speak to someone who works in this area every day, you can book an online consultation with a care provider on Uma. They are independent doctors and specialists who consult through the Uma platform rather than being employed by it, and they work with patients in Belgium and the Netherlands. Navigating exactly the differences described on this page is part of their ordinary week.

The content on this page is intended for informational purposes and does not replace medical advice. Please consult a physician for a personal assessment.

Sources

National Institute for Health and Care Excellence (2015, updated 2026). Menopause: identification and management. NICE guideline NG23. https://www.nice.org.uk/guidance/ng23
Rozenberg, S. (2026). Belgian Menopause Society: Praktische richtlijnen voor de aanpak van de menopauze. Belgian Menopause Society. Published by Gedeon Richter Benelux as responsible publisher. https://www.menopausesociety.be/nieuwsbericht/guidelines-menopause-bms/
RIZIV-INAMI (2024). Consensusvergadering: Aanpak van menopauze, juryrapport, 30 mei 2024. https://www.riziv.fgov.be/SiteCollectionDocuments/consensus_lange_tekst_20240530.pdf
Belgisch Centrum voor Farmacotherapeutische Informatie (2025). Hormoontherapie tijdens de (peri)menopauze: voor- en nadelen. Folia Pharmacotherapeutica, January 2025. https://www.bcfi.be/nl/hormoontherapie-tijdens-de-perimenopauze-voor-en-nadelen/
Nederlands Huisartsen Genootschap (2022). NHG-Standaard De overgang (M73), version 3.0. https://richtlijnen.nhg.org
NVOG and Dutch Menopause Society (2025). Praktische handleiding hormoonsuppletietherapie (HST) en geregistreerde niet hormonale farmacotherapie. https://richtlijnendatabase.nl
International Menopause Society (2026). IMS Recommendations and Key Messages on Women's Midlife Health and Menopause. https://www.imsociety.org
Roman, M.P., Ciortea, R., Doumouchtsis, S.K., et al. (2024). A quality assessment and systematic review of clinical practice guidelines on hormone replacement therapy for menopause using the AGREE II instrument. European Journal of Obstetrics and Gynecology and Reproductive Biology, 303, 294–301. doi:10.1016/j.ejogrb.2024.10.046
Makary, M.A., Nguyen, C.P., Høeg, T.B., Tidmarsh, G.F. (2025). Updated Labeling for Menopausal Hormone Therapy. JAMA, published online 10 November 2025.

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Medically reviewed by

Dr. William Declerck

Physician

6 in 10 women experience brain fog during menopause.

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Why two doctors can give you opposite advice about HRT

In short