Menstria · start at 35
Start tracking before you need it.
Perimenopause is not usually diagnosed by a blood test. In most women it is diagnosed from the pattern of their own cycles — which means the evidence has to already exist by the time anyone goes looking for it. Blood tests have real uses here, and they are more specific and more limited than the marketing suggests. What each one actually measures is below.
The criterion for entering the transition is a persistent difference of seven days or more between one cycle and the next. You cannot detect a change without a baseline to measure it against. That is the whole argument for starting at 35: not because anything is happening yet, but because in a few years someone will want to know what normal looked like for you, and only you can supply that.
Why not just get your hormones tested? Because during the transition the hormones themselves are unstable — that instability is the transition. A value can read menopausal one month and normal the next. So a single result usually cannot confirm or exclude anything, which is why ACOG, NICE and The Menopause Society all direct that the diagnosis be made from age, symptoms and cycle change in women over 45.
That is not the same as saying tests are useless. It means each one answers a narrow question, and knowing which question is the difference between a useful result and an expensive one. The test-by-test guide is below.
Your period start dates
The first day of bleeding each month, not spotting. Add them as they happen, or enter what you can remember. Three cycles gives a first read; twelve gives a real baseline.
Where this is stored. On this device, in this browser, and nowhere else. Nothing is uploaded, and there is no account. Clearing your browser data will erase it, so use Export before you change devices or clear your history.
The blood tests people talk about
Every one of these is real, and every one answers a narrower question than it is usually sold as answering. The column that matters is the last one.
The ovarian and pituitary hormones
| Test | What it measures | What it means, and when it helps |
|---|---|---|
| FSH follicle-stimulating hormone |
The signal from the pituitary telling the ovaries to mature a follicle. It rises as the ovaries respond less, so the brain shouts louder. | In established postmenopause a high FSH is a reliable marker. In perimenopause it is not: it oscillates week to week, so one value can look menopausal and the next normal. Useful between 40 and 45 with symptoms, and under 40 where premature ovarian insufficiency is suspected. Not interpretable on combined hormonal contraception. A normal FSH does not exclude perimenopause. |
| LH luteinising hormone |
The pituitary signal that triggers ovulation. Rises alongside FSH as ovarian function declines. | Adds little to FSH for this purpose and is not needed to make the diagnosis. Its main uses are elsewhere — ovulation prediction kits, and the LH-to-FSH ratio in PCOS. |
| Estradiol E2, the main estrogen |
The estrogen produced by developing follicles. | The most misunderstood result in this list. Estradiol does not fall steadily through the transition — it swings, and can run higher than in your thirties before it drops. A single value is a snapshot of a moving target. Genuinely useful for monitoring absorption on some forms of hormone therapy, and in assessing POI. |
| AMH anti-Müllerian hormone |
Produced by small growing follicles, so it tracks roughly how many are left. The best single marker of ovarian reserve. | Strongly linked to age at menopause across populations, but individual prediction is imprecise enough to be of little clinical value except at the extremes — and repeat measurements do not improve it. Routine AMH to predict your own menopause is not recommended, whatever a commercial panel implies. It is genuinely valuable for fertility planning, and a very low value in a young woman flags POI risk. Falsely low on recent hormonal contraception, and high in PCOS. |
| Inhibin B | Another follicle product that falls early in ovarian ageing. | A research marker. It declines before FSH rises, which makes it interesting, but it is not used in routine practice and adds nothing to a decision you would otherwise make. |
| Progesterone mid-luteal, often called "day 21" |
Confirms whether you ovulated in that particular cycle. Only meaningful about seven days before the next period — which in an irregular cycle is a date nobody can predict. | Does not diagnose perimenopause. It can confirm that a given cycle was anovulatory, which explains that cycle. Its timing problem is exactly why cycle records beat single blood draws in this window. |
The tests that rule out something else
These matter more than most people expect, because several conditions produce the perimenopause symptom list and are treatable in completely different ways.
| Test | Why it is on the list |
|---|---|
| TSH, sometimes with free T4 | Thyroid disease imitates the entire picture — cycle change, fatigue, mood change, temperature intolerance, hair and weight change. It is cheap, definitive, and treatable. If only one test is done, this is often the one worth doing. |
| Full blood count and ferritin | Heavy or frequent bleeding in the transition causes iron deficiency, which produces the fatigue and brain fog often attributed to hormones. Ferritin falls before haemoglobin does, so a normal blood count alone can miss it. |
| Prolactin | Raised prolactin suppresses ovulation and causes irregular or absent periods. Has a short and specific differential, including several common medications. |
| hCG pregnancy test | Ovulation in the transition is unpredictable rather than absent. A missed period at 46 is not proof of anything until this is negative. |
| Testosterone, SHBG, DHEA-S | Not for diagnosing perimenopause. Relevant where there is excess hair growth, acne or scalp hair loss, and in some discussions of low libido. |
| Lipids, HbA1c, blood pressure | Not diagnostic either — but cardiovascular and metabolic risk changes across the transition, and this is the window where finding it early matters most. Arguably the most valuable bloods drawn at this stage. |
The ones sold directly to you
| Product | What to know |
|---|---|
| At-home FSH kits | They detect elevated FSH in urine, and they do it reasonably well. The problem is not the assay, it is the biology: FSH swings, so a positive result on one day means very little. Treat it as a conversation starter, never as a diagnosis. |
| DUTCH and salivary hormone panels | Marketed as more comprehensive than blood. They measure hormone metabolites rather than the hormones themselves, reference ranges are not established for this purpose, and no major menopause guideline recommends them for diagnosis or for guiding treatment. |
| Large "hormone panels" | The commercial appeal is breadth. The clinical problem is that a wide panel of unstable values in a woman who is by definition hormonally unstable generates results needing explanation rather than answers. It is also how normal findings get treated as abnormal. |
The short version
If you are over 45 with changing cycles and symptoms, the diagnosis is clinical and blood tests are usually unnecessary. If you are 40 to 45 with symptoms, FSH may help. If you are under 40, get assessed properly, because the answer changes management. And at any age, TSH and ferritin are worth more than a hormone panel, because they find things that are treatable and are otherwise put down to hormones.
None of this replaces the record of your own cycles. That is the one piece of evidence no laboratory can generate for you afterwards.
AMH: individual prediction of age at menopause is imprecise except at extremes, and repeated measurements do not materially improve it — see sources. FSH indications per NICE NG23. Clinical-diagnosis-over-testing position per ACOG, NICE and The Menopause Society 2022.
What the tracker is looking for
| Finding | What it means |
|---|---|
| A persistent difference of 7 days or more between consecutive cycles | The STRAW+10 criterion for entering the early menopausal transition. This is the one that needs a baseline to see. |
| An interval of 60 days or more without a period | The criterion for the late transition. Vasomotor symptoms are most likely in this window. |
| Cycles becoming subtly shorter while still regular | Often the earliest change of all, in the late reproductive stage — and invisible without records. |
| Cycles under 24 or over 38 days | Outside the FIGO normal range for adults, whatever your age. Worth raising regardless of the transition. |
| 12 months with no period | Menopause has occurred, dated retrospectively to the final period. |
STRAW+10 staging criteria; FIGO System 1 frequency range 24–38 days. Full citations on the sources page.
Tracking does not replace getting these looked at. Bleeding between periods. Bleeding after sex. Periods suddenly much heavier, or lasting more than 8 days. And any bleeding at all once you have gone 12 months without one — that is postmenopausal bleeding and it is always investigated.
Evidence base
Sources
- Harlow SD, Gass M, Hall JE, et al. Executive summary of the Stages of Reproductive Aging Workshop +10: addressing the unfinished agenda of staging reproductive aging. J Clin Endocrinol Metab. 2012;97(4):1159–1168. Source of the staging criteria this tool applies: entry to the early transition at a persistent difference of ≥7 days between consecutive cycles, and the late transition at an interval of ≥60 days. Flagged for bibliographic re-verification — the 2012 executive summary appeared in parallel in several journals with differing pagination.
- Munro MG, Critchley HOD, Fraser IS; FIGO Menstrual Disorders Committee. Int J Gynaecol Obstet. 2018;143(3):393–408. FIGO System 1: normal cycle frequency 24 to 38 days, duration 8 days or fewer. Applied here independently of menopausal staging, because a cycle outside that range is worth attention whatever the cause.
- The 2022 hormone therapy position statement of The North American Menopause Society. Menopause. 2022;29(7):767–794. Basis for the statement that routine serum hormone testing is rarely needed to guide treatment decisions, and that candidacy rests on symptoms, age and time since the final period rather than on a laboratory threshold.
- National Institute for Health and Care Excellence. Menopause: diagnosis and management. NICE guideline NG23. Source of the narrow indications for FSH testing used on this page: ages 40 to 45 with menopausal symptoms, and under 40 where premature ovarian insufficiency is suspected. Flagged for verification of the current version and date.
- Nelson SM, Davis SR, Kalantaridou S, Lumsden MA, Panay N, Anderson RA. Anti-Müllerian hormone for the diagnosis and prediction of menopause: a systematic review. Hum Reprod Update. 2023;29(3):327–346. Source of the AMH position taken here: strong population-level association with age at menopause, but individual prediction imprecise enough to be of little clinical value except at extremes of value; diagnostic use in individuals not rigorously examined; very low values in young women do carry meaning for POI risk. Author list and pagination taken from the journal record; verify before formal citation.
- Depmann M, Eijkemans MJC, Broer SL, et al. Does AMH relate to timing of menopause? Results of an individual patient data meta-analysis. J Clin Endocrinol Metab. 2018;103(10):3593–3600. Individual patient data meta-analysis. AMH predicted time to menopause, but individual predictions showed limited precision — particularly for early menopause — making clinical application troublesome, with only a minor gain over age alone. Flagged for verification of the full author list.
- American College of Obstetricians and Gynecologists. Patient guidance on the menopause years. Basis for the statement that perimenopause can usually be identified from age, symptoms and menstrual change without a blood test. Flagged for citation of the specific current document.