6 min - BioSense Team - 2026-06-24
- level:understanding
- préménopause
- biomarqueurs
- hormones
- ménopause
Perimenopause is a normal physiological transition, not an illness. Yet it comes with measurable biological changes that can explain some of the shifts you experience day to day. This article reviews the biomarkers that evolve from age 40, what they mean, and why their reading must always be placed in context.
You're 45, your cycles have been breaking up for a few months, a fatigue that doesn't feel like before, sometimes fleeting hot flushes. Your usual blood panel shows nothing abnormal, and yet you know something is changing. Biology can shed light on this transition — without turning it into something medical.
Here are the biomarkers that evolve during perimenopause, what they really tell us, and why the same result can mean different things depending on where you are.
Perimenopause: what exactly is it?
Perimenopause — sometimes called the menopausal transition — is the period of hormonal transition that precedes menopause. It begins on average between 40 and 50, and most often lasts four to eight years before confirmed menopause (defined as twelve consecutive months without periods). Menopause occurs on average around 51 in France, but with significant individual variation.
This transition is physiological, not pathological. All women go through it, at a pace and intensity that are their own. Some feel almost nothing, others experience marked manifestations. Neither the absence nor the presence of symptoms signals a problem: it is normal variability.
Does that mean a systematic hormonal work-up is needed in perimenopause? Not necessarily. French and international guidelines do not recommend routine hormonal testing to confirm perimenopause, which is diagnosed mainly from how you feel and how your cycles evolve. Hormonal testing becomes more useful in cases of diagnostic doubt, suspected early menopause (before 40), or to adapt a treatment decision with your doctor.
Key point — Perimenopause is a normal physiological transition, on average between 40 and 50, lasting four to eight years before menopause. It does not systematically require a hormonal work-up — how you feel and how your cycles evolve remain front and centre.
The hormonal biomarkers that change
Three hormonal markers can be informative when testing is indicated. None is prescribed routinely; all are to be discussed with your doctor.
FSH (follicle-stimulating hormone)
FSH is secreted by the pituitary gland to stimulate the ovaries. As the ovarian reserve declines, the pituitary secretes more of it to maintain function. FSH therefore rises gradually during perimenopause, and reaches high values in confirmed postmenopause. An FSH above 25-30 IU/L is often suggestive of an advanced transition — but during perimenopause, its values can fluctuate from month to month, which makes a single measurement of little use. It is the evolution over time, more than the isolated figure, that provides information.
Estradiol
Estradiol is the main estrogen produced by the ovaries. During perimenopause, its levels become erratic before falling lastingly in postmenopause. A single measurement is rarely useful, because it can be normal one month and low the next. It is precisely this variability that makes the transition unsettling at times.
AMH (anti-Müllerian hormone)
AMH is secreted by the ovarian follicles. Its level reflects the remaining ovarian reserve. It declines gradually with age and becomes very low at the end of perimenopause. AMH is not reimbursed by the French health insurance outside specific indications (typically as part of a medically assisted reproduction work-up). It can be useful to estimate the "time margin" before menopause, but its value in everyday practice remains debated.
Key point — FSH, estradiol, AMH: these hormonal markers can inform on the transition, but they fluctuate. A single measurement is rarely decisive. The clinical context and tracking over time remain essential.
The metabolic biomarkers to monitor
This is probably where the biological reading is most valuable in practice. Beyond hormones, the transition toward menopause comes with metabolic changes that deserve attention, because they have long-term consequences for cardiovascular, bone and metabolic health.
The lipid panel: total cholesterol, LDL, HDL, triglycerides
Estrogens have a protective effect on the lipid profile: they tend to lower LDL and raise HDL. As estrogens decline during perimenopause, this benefit fades. Many women see their LDL cholesterol rise gradually after 45, without any change in dietary behaviour. This is a physiological evolution that must be tracked, because women's cardiovascular risk rises significantly after menopause.
Blood glucose and HbA1c
The hormonal transition often comes with mild insulin resistance. The distribution of body fat changes (a tendency to accumulate around the abdomen), and insulin sensitivity decreases. Regular monitoring of fasting blood glucose and, depending on risk factors, HbA1c makes it possible to spot prediabetes before it becomes diabetes.
TSH (thyroid function)
Thyroid disorders, particularly hypothyroidism, are more common in women over 50. Their symptoms (fatigue, weight gain, feeling cold, dry skin) partly overlap with those of perimenopause, which can cause confusion. A TSH measurement when suggestive symptoms are present is useful to distinguish the two.
Vitamin D and bone health
The loss of estrogens accelerates bone loss. Vitamin D, which plays a key role in calcium absorption and bone mineralisation, takes on particular importance. A reminder: since 2014, the 25-OH vitamin D assay is only reimbursed in specific indications. Outside these, testing is possible but at your own expense. Supplementation can often be prescribed without prior testing, in line with current guidelines.
Key point — Cholesterol, blood glucose, TSH, vitamin D: these four metabolic families evolve during perimenopause and deserve regular monitoring. Women's cardiovascular risk rises significantly after menopause — it is during the transition that you can act.
Why these results must be read in context
No biological figure has meaning in isolation during perimenopause. There are three reasons for this.
First, the variability from one woman to another is considerable. Some reach menopause with unchanged metabolic markers; others see their LDL rise by 20% in two years. Neither is abnormal; they are different trajectories.
Second, the evolution over time matters more than today's figure. An FSH of 18 IU/L can be normal in a 50-year-old woman whose FSH was 8 IU/L two years earlier — the trajectory tells the story of the transition. The same FSH of 18 IU/L can be very different in a 38-year-old woman, where it would instead suggest premature ovarian insufficiency warranting a specialist opinion.
Finally, the personal context — symptoms, family history of early menopause, current treatments, lifestyle — changes the interpretation. The same value does not have the same meaning depending on your history.
The BioSense method
Perimenopause is precisely the kind of transition where context makes all the difference. BioSense cross-references your results with your health questionnaire — age, personal and family history, treatments, lifestyle, any symptoms, reason for the prescription — and with official guidelines (HAS, French and international learned societies). Your results are tracked over time, which is essential during this period of natural variation.
*ChatGPT answers you. BioSense knows you.* *BioSense, your prevention companion.* BioSense does not provide a diagnosis and does not replace your doctor. It is a prevention companion that helps you understand, ask the right questions and act day to day.
Preparing for your medical appointment: three useful questions
If you are in perimenopause or wondering whether you're entering it, here are three questions to prepare for your next consultation:
- Given my age, my cycles and any symptoms, is a hormonal work-up genuinely useful in my case?
- Beyond hormones, how can I best monitor my cardiovascular, metabolic and bone risk in the years to come?
- How often should I repeat a panel to track the evolution of my metabolic profile (lipids, blood glucose, vitamin D, TSH)?
These questions steer the conversation beyond symptoms alone, toward long-term health.
*This article is for informational purposes only and is neither medical advice nor a diagnosis. For any questions about your health, consult your doctor.*
Import your blood test into BioSense and receive a plain-language explanation of each of your biomarkers, contextualised to your profile and your life stage, with tracking over time. Your data is hosted in France on infrastructure certified for hosting health data (HDS).
[→ Import my report](/en/onboarding/upload)
Sources and methodology
- High Authority for Health (HAS) — Reassessment of menopausal hormone therapy (MHT); published online on 14 October 2025.
- French National College of Gynaecologists and Obstetricians (CNGOF) and the Study Group on Menopause and Hormonal Ageing (GEMVI) — Clinical practice guidelines: menopause (Gynécologie Obstétrique Fertilité & Sénologie, Vol. 49, No. 5, May 2021).
- Trémollieres FA, André G, Letombe B et al. — Management of postmenopausal women: position statement of the French Society for Menopause and Hormonal Aging (Maturitas 2022;163:62-81).
- The Menopause Society (formerly NAMS) — The 2022 Hormone Therapy Position Statement (Faubion SS, Crandall CJ, Davis L et al., Menopause 2022;29(7):767-794, DOI 10.1097/GME.0000000000002028).
- French Society of Endocrinology (SFE) — Guidelines on phosphocalcic metabolism and bone health.
- Mach F, Baigent C, Catapano AL et al. — 2019 ESC/EAS Guidelines for the management of dyslipidaemias (European Heart Journal, DOI 10.1093/eurheartj/ehz455), with Focused Update 2025 (DOI 10.1093/eurheartj/ehaf190); SCORE2 and SCORE2-OP (Eur Heart J 2021;42(25):2439-2454 and 2455-2467).
- Research and Information Group on Osteoporosis (GRIO) — Position statement on vitamin D (Souberbielle JC, Joint Bone Spine 2020; Pickering ME et al.).
- UNCAM — Decisions of 14 August 2014 and 25 November 2021 on the reimbursement of vitamin D testing.
*BioSense methodology: our content draws on official French guidelines (HAS, ANSM, Santé Publique France, INSERM, Assurance Maladie, Anses), European guidelines (ESC, EASD, NICE) and international ones (WHO, ADA, AHA, NIH), as well as specialised learned societies (SFE, SFBC, CNGOF, GEMVI, GRIO). It is reviewed with an educational approach before publication.*