Perimenopause Bone Health: The Prevention Window

What is perimenopause, and why does it matter so much for your bones?

Perimenopause is the transition leading up to your final menstrual period, when oestrogen begins to fluctuate and fall — and because oestrogen is one of the skeleton's most important protectors, this is when bone loss can quietly accelerate. Oestrogen helps keep bone breakdown and bone building in balance. As levels become erratic and then decline, that balance tips towards breakdown, and bone density starts to slip.

The crucial point is timing. Most women associate bone problems with the years after menopause, but the research shows the skeleton starts changing while periods are still happening. A review in Obstetrics and Gynecology Clinics of North America notes that bone loss at the lumbar spine and femoral neck became evident as follicle-stimulating hormone rose into the menopausal range — roughly two years before the final menstrual period Lo, Burnett-Bowie and Finkelstein, 2011. That early start is exactly why perimenopause is the window where prevention has the most to offer.

When does bone loss actually start — and how fast does it happen during perimenopause?

Bone loss typically becomes measurable in late perimenopause and is fastest around the final period — and the pace is brisk enough to matter. The Study of Women's Health Across the Nation (SWAN), one of the largest multi-ethnic studies of the menopause transition, mapped this in detail.

In late perimenopause, women lost roughly 1.8–2.3% of bone density a year at the lumbar spine and about 1.0–1.4% a year at the hip SWAN data, summarised in Lo et al., 2011. Before this phase, loss was negligible: SWAN found essentially no change at the spine in the years before the transmenopausal window opened. Once it opened, the decline was clear — Caucasian women lost about -2.46% a year at the lumbar spine and -1.76% a year at the femoral neck across the transmenopausal phase Greendale et al., 2012.

Stacked up over the whole transition, that adds to roughly a 10.6% loss at the spine and 9.1% at the hip over ten years Greendale et al., 2012. A later analysis put the rapid-loss phase at about 2.5% a year at the spine and 1.8% a year at the femoral neck in White women across roughly three years straddling the final period Karlamangla et al., 2018. The practical message: this is not a slow drift you can leave for later.

What causes accelerated bone loss in perimenopause?

The main driver is the fall in oestrogen, which lets bone breakdown outpace bone building — but emerging evidence points to other contributing factors too. As the British Dietetic Association puts it, falling oestrogen increases the speed at which calcium and other minerals are lost from bone British Dietetic Association, 2023. That hormonal shift is the headline cause.

There is also an under-recognised angle worth flagging honestly. Perimenopause involves more cycles without ovulation, and ovulation is what produces progesterone in the second half of the cycle.

Alongside hormones, the ordinary risk factors still apply: low vitamin D, low calcium and protein intake, inactivity, smoking and a thin frame all add to the picture. Karlamangla and colleagues, for instance, reported that a vitamin D level below 20 ng/mL was associated with an 85% higher risk of non-traumatic fracture in midlife women Karlamangla et al., 2018.

How do you know if your bones are already being affected?

Usually, you don't — and that is the problem. Bone loss is silent. There is no ache, no symptom, no warning until a bone breaks or a scan reveals it. Worryingly, the consequences arrive earlier than many assume: in SWAN, between the ages of 42 and 58, one in six women had at least one fracture Karlamangla et al., 2018.

That silence is why a baseline measurement matters. The only reliable way to know whether your bone density is holding or falling is to measure it. Researchers are actively looking for accessible ways to flag risk early — one 2025 cross-sectional study tested a blood-marker approach (combining a bone-turnover marker with oestradiol) as a lower-cost, radiation-avoiding way to spot high-risk perimenopausal women where bone scanning is unavailable Feng, Xiao and Zhang, 2025. That is a serum-biomarker method rather than a scan, and it is early research — but it shows the appetite for early, low-burden screening in this group is real.

What lifestyle changes make the biggest difference during the prevention window?

Movement and nutrition are the two levers most within your control — and the evidence behind them is consistent. None of this stops the hormonal shift, but it can slow the rate of loss while it matters most.

• Resistance and weight-bearing exercise. A 2025 scoping review pointed to resistance training at a meaningful intensity, at least twice a week and sustained over months, as the kind of loading that supports bone Frontiers in Reproductive Health, 2025. NICE likewise recommends explaining to women the importance of maintaining muscle mass and strength through physical activity NICE NG23, first published 2015, last updated 2026.
• Adequate protein to defend the muscle that loads your bones — the BDA suggests pairing protein with resistance exercise two to three times a week British Dietetic Association, 2023.
• Calcium-rich foods, aiming for two to three servings a day, per BDA guidance British Dietetic Association, 2023.
• Vitamin D. UK guidance generally suggests a 10 microgram daily supplement, especially through autumn and winter, and the BDA advises that women over 65 consider it year-round. The right approach for you is best confirmed with a clinician.

Does HRT protect bones during perimenopause — and who should consider it?

For suitable women, hormone replacement therapy is one of the most effective ways to protect bone through the transition — but it is an individual clinical decision, not a blanket recommendation. Because the loss is driven by falling oestrogen, replacing it directly addresses the cause.

The Royal Osteoporosis Society states that HRT appears to be as effective as other osteoporosis medicines at lowering the chance of broken bones in postmenopausal women, and that it is recommended where menopause is early — before age 45 Royal Osteoporosis Society. NICE adds an important nuance: the fragility-fracture benefit is maintained during treatment but decreases once treatment stops NICE NG23, first published 2015, last updated 2026. The supporting trial evidence is real — a 2025 scoping review synthesising data including the Women's Health Initiative noted statistically significant reductions of around a third in hip fracture for certain HRT regimens, with HRT combined with exercise improving bone density more than exercise alone Frontiers in Reproductive Health, 2025.

Timing matters: the ROS notes HRT is usually started before age 60, after which the risks may begin to outweigh the benefits for bone protection. Whether HRT is right for you depends on your symptoms, your risk profile and your preferences — a conversation to have with your GP or a menopause specialist. Notably, there are still no established guidelines specifically for treating and preventing osteoporosis in perimenopausal women Lo, Burnett-Bowie and Finkelstein, 2011, which makes knowing your own numbers all the more useful.

What does early bone assessment look like in the UK, and how does radiation-free REMS scanning fit in?

Early assessment means measuring your bone density before symptoms appear, so you have a baseline to track against through the transition. NICE recommends that clinicians give advice on bone health and discuss it at review appointments NICE NG23, first published 2015, last updated 2026 — but in practice there is no routine NHS bone-density programme for women in their 40s, so most perimenopausal bone loss goes unmeasured.

A baseline assessment is worth considering if you have early menopause, a family history of osteoporosis, or other risk factors. It answers the one question that matters: is my bone density changing, and do I need to act?

Why a radiation-free REMS assessment suits the prevention window

Standard DEXA scans use a small dose of X-ray radiation, which makes frequent re-scanning less ideal. REMS (Radiofrequency Echographic Multi Spectrometry) is radiation-free, so it can be repeated safely year on year to track how your bones change across the menopause transition — exactly the kind of monitoring this prevention window calls for. (REMS is the technology Screen My Bones uses; the studies cited above measured bone change by other methods rather than testing REMS itself.)

You can book a radiation-free bone health assessment, read more about our bone health assessment and the science behind our approach, or see where we screen across the UK.

The bottom line

Perimenopause is not the moment bone loss becomes irreversible — it's the moment it becomes worth acting on. The evidence is clear that loss can start years before your final period and move quickly through the transition, yet it is also the stage where exercise, nutrition and, for the right women, HRT have the most to offer. The missing piece for most women is simply knowing where they stand. A baseline measurement turns a silent process into something you can see, track and protect against.

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This article is part of our menopause and bone health series. If you're also weighing up weight-loss medications, see our guide to Ozempic and bone loss.