What is perimenopause? The complete guide
8 min read
Perimenopause can begin a decade before your last period — and for many women, it starts in their early 40s, sometimes even late 30s. Yet it often goes unrecognised for years. Here's what's actually happening hormonally, what to expect, and when to seek support.
What is perimenopause?
Perimenopause is the transitional phase leading up to menopause — the point at which you've gone 12 consecutive months without a period. During perimenopause, your ovaries gradually produce less oestrogen and progesterone. This process is rarely smooth or linear. Hormone levels fluctuate unpredictably, which is why symptoms can feel inconsistent and confusing.
When does it start?
Most women enter perimenopause in their mid-to-late 40s, but it can begin as early as the mid-30s. On average it lasts 4–8 years, though this varies considerably. You may not even notice it beginning — the earliest signs are often subtle changes in your menstrual cycle.
What causes the symptoms?
Oestrogen receptors exist throughout the body — in the brain, bones, cardiovascular system, skin, bladder, and vagina. As oestrogen fluctuates and eventually declines, all of these systems are affected. This is why the symptom list is so long and varied, and why menopause is a whole-body experience rather than just a "reproductive" one.
How is it diagnosed?
Perimenopause is typically a clinical diagnosis based on age, symptoms, and changes to your menstrual cycle. Blood tests (FSH, oestradiol) can be helpful but are often unreliable in perimenopause because hormone levels fluctuate significantly day to day. A single normal result doesn't rule it out.
What should I do if I think I'm in perimenopause?
Start tracking. Keeping a record of your symptoms — their frequency, severity, and any patterns — is genuinely useful. It helps you understand what's happening, identify triggers, and gives your doctor the information they need to support you. Vida is designed to make this easy.
Clinical reference points
Reviewed against these public guidance sources in September 2026. Content is educational and is not represented as clinician-reviewed.
Educational content only. This guide is intended to inform, not to replace medical advice. Always discuss symptoms and treatment options with a qualified healthcare provider who knows your full history.
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