Estradiol Levels in Perimenopause: A Practical Guide
Find out what estradiol is, how levels change in perimenopause, what the numbers mean, and how to use results to guide your care.
What Is Estradiol?
Estradiol is the most potent form of oestrogen in reproductive-age women. It is produced mainly by the ovarian follicles and plays a central role in regulating the menstrual cycle, maintaining bone density, protecting cardiovascular health, and supporting brain function. During perimenopause, estradiol levels become unpredictable. They may spike high, creating breast tenderness and heavy periods, then drop sharply, triggering hot flashes and low mood.
How Estradiol Changes During Perimenopause
Early in perimenopause, estradiol can actually surge above normal premenopausal ranges as the pituitary pushes harder to stimulate ageing follicles. This phase can feel intense, with worsened PMS, heavy bleeding, and mood swings. As perimenopause progresses, estradiol becomes erratic and gradually trends lower. By menopause, ovarian production has largely stopped and levels fall well below 100 pmol/L, sometimes dropping close to zero.
Why Testing Estradiol Can Be Tricky
Because estradiol fluctuates so much during perimenopause, a single blood test is rarely definitive. A normal result one day does not rule out oestrogen deficiency, and a low result does not always mean symptoms will persist. Some clinicians argue that diagnosing perimenopause based on symptoms and menstrual history is more reliable than relying on a single estradiol reading. Testing is most useful when done repeatedly or alongside FSH.
How to Get Your Estradiol Tested
A serum oestradiol test is available through your GP. It is usually taken on days two to five of your menstrual cycle for a baseline reading. You can request it as part of a wider hormonal panel that includes FSH, LH, and sometimes thyroid function. Some private clinics offer extended panels with more context around timing and your symptom history. A saliva or urine test is an alternative but less commonly used in standard clinical practice.
Understanding the Numbers
In reproductive-age women, mid-cycle estradiol typically peaks between 400 and 1,500 pmol/L. Early follicular phase levels of 100 to 300 pmol/L are common. In perimenopause, readings below 100 pmol/L between periods suggest declining ovarian function. Post-menopausal levels are often below 50 pmol/L. On HRT, target estradiol levels vary depending on the type and dose of treatment. Your prescriber will advise on what range is appropriate for you.
Using Results to Guide Your Next Steps
Low estradiol alongside high FSH and clear symptoms strongly supports a perimenopause or menopause diagnosis. From there, conversations about HRT, bone protection, and cardiovascular health become relevant. High estradiol with a heavy cycle and low progesterone points toward oestrogen dominance and may guide treatment differently. Either way, having a documented result gives your doctor a baseline for future comparison. Pairing that data with a symptom log makes for a more productive clinical conversation.
Related reading
Get your personalized daily plan
Track symptoms, match workouts to your day type, and build a routine that adapts with you through every phase of perimenopause.