What are the first signs of perimenopause?

The earliest signs of perimenopause are usually changes in your periods, which get shorter, longer, lighter, heavier or less predictable, often alongside new sleep problems, mood changes and the first hot flushes.

Because progesterone tends to fall first, some of the very earliest hints arrive before your cycle changes much, sometimes by years:

• Disrupted sleep, especially waking around 3 to 4am
• Heightened PMS and breast tenderness
• New anxiety or irritability

As oestrogen starts to fluctuate too, the more familiar symptoms appear: irregular cycles, hot flushes and night sweats, brain fog, joint aches, lower libido and mood changes. Many women are caught off guard because they expect perimenopause to arrive later and look more dramatic than it does. It typically begins in your forties, sometimes the late thirties, and is diagnosed on your symptoms and age, not a single blood test, since hormones swing too much day to day to pin down.

The reason progesterone-related symptoms come first is worth understanding. In the early transition you often still ovulate, but less reliably, and cycles without ovulation produce little progesterone while oestrogen carries on. That relative shortfall of the calming, sleep-supporting hormone is why sleep and mood frequently wobble before hot flushes ever begin, and why the first signs are so easy to mistake for ordinary stress.

The transition also lasts longer than most people expect, around four years on average and up to eight to ten for some women, which is part of why the early signs are so easily misread. In the beginning they are mild and intermittent, so they get attributed to stress, a busy life or a thyroid problem, and the perimenopause link is only made in hindsight.

What to do: if you are in your forties with changing periods and any of these symptoms, perimenopause is the likely explanation, and you do not need to wait until periods stop to get help. Tracking your cycle and symptoms gives you and your GP a clearer picture, and lifestyle changes and HRT where appropriate work during the transition. Our free hormone quiz can help you see how your symptoms map to the hormonal picture.