DEXA Scan Guide for Perimenopause: What to Expect and When to Get One
Everything you need to know about DEXA bone density scans during perimenopause, including when to ask for one and how to read your results.
Why Bone Density Testing Matters During Perimenopause
Perimenopause is the window when bone loss accelerates. In the two to five years surrounding the final menstrual period, some women lose as much as two to three percent of their bone mass each year. That cumulative loss can tip a woman from normal bone density into osteopenia or osteoporosis without any obvious symptoms. A DEXA scan is the standard way to measure this loss before a fracture happens. DEXA stands for dual-energy X-ray absorptiometry. It uses two low-dose X-ray beams to measure the mineral content of your bones, most commonly at the hip and lumbar spine, the two sites where osteoporotic fractures cause the most harm. The radiation dose is tiny, roughly equivalent to a few hours of natural background radiation, so the test is considered very safe.
When Should You Ask for a DEXA Scan
Current guidelines in the UK and USA suggest routine bone density screening for women aged 65 and over. However, many perimenopausal women have risk factors that justify an earlier scan. You should discuss a DEXA scan with your doctor if you are under 65 and have any of the following: early or premature menopause before age 45, a family history of hip fracture, long-term use of corticosteroids (more than three months), a history of an eating disorder, low body weight (BMI under 19), inflammatory conditions such as rheumatoid arthritis or coeliac disease, heavy smoking or alcohol use, or a previous fragility fracture. If you have had multiple risk factors for years, your bone loss may already be clinically significant even in your 40s. Do not wait until you have a fracture to investigate. A conversation with your GP or a menopause specialist is the best starting point.
How to Read Your T-Score and Z-Score
Your DEXA results include two numbers. The T-score compares your bone density to a young healthy adult of the same sex at peak bone mass. A T-score of -1.0 or above is considered normal. Between -1.0 and -2.5 is osteopenia, meaning lower than optimal density but not yet osteoporosis. A T-score of -2.5 or below indicates osteoporosis. The Z-score compares your density to other people of your age and sex. A Z-score below -2.0 suggests your bone loss is more than would be expected for your age, which may indicate a secondary cause such as low vitamin D, thyroid disease, or malabsorption. If your Z-score is low, further blood tests are usually recommended before starting treatment. Keep a copy of your DEXA report so you can compare results at your next scan.
What Happens During the Scan
A DEXA scan is quick and straightforward. You lie fully clothed on a padded table while a mechanical arm passes over your body. There is no enclosed tunnel as with an MRI. The hip and spine scan together take about 10 to 20 minutes. You may also have a vertebral fracture assessment, a side-on image of your spine taken in the same session, which can detect silent compression fractures that would otherwise go unnoticed. No special preparation is needed, but you should avoid calcium supplements for 24 hours before the scan as high doses of calcium can marginally affect readings. You do not need to fast. Wear comfortable clothing without metal fasteners, as zips and underwire bras may need to be removed. Results are usually sent to your referring doctor within a week.
What Happens After Your Results
If your bone density is normal, you may not need another scan for five to ten years unless new risk factors develop. If you have osteopenia, your doctor will typically recommend lifestyle measures: weight-bearing exercise, adequate calcium and vitamin D, reducing alcohol, and stopping smoking. Some women with osteopenia and multiple risk factors are offered medication, particularly if their FRAX fracture risk score (a 10-year probability calculation) is elevated. If you are diagnosed with osteoporosis, treatment options include bisphosphonates, denosumab, or raloxifene. HRT is also recognised for its bone-protective effects and is often prescribed for perimenopausal women who have osteopenia or osteoporosis alongside other menopause symptoms. Your next scan after starting treatment is usually repeated in two years to monitor response.
Lifestyle Steps to Support Bone Density Alongside Scanning
A DEXA scan tells you where your bones are today. What you do next determines the trajectory. Weight-bearing exercise is the single most modifiable factor. Walking, jogging, dancing, and resistance training all stimulate bone formation. Aim for at least 150 minutes of moderate activity per week, with two sessions of muscle-strengthening exercise. Calcium requirements for perimenopausal women are around 1,000 to 1,200 mg per day, ideally from food sources such as dairy, fortified plant milks, tinned sardines with bones, almonds, and leafy greens. Vitamin D is needed for calcium absorption. Most women in northern latitudes need a supplement, particularly in winter. A blood test can check your vitamin D level. Smoking accelerates bone loss and should be stopped. Alcohol in excess of 14 units per week has a measurable negative effect on bone. These changes work at any stage, including after a diagnosis.
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