Am I going crazy? No — this is perimenopause

It often starts quietly. Your period shows up a week early, then skips a month. You're lying awake at 3am for no reason, or waking up drenched. You snap at someone you love and don't recognise yourself. You walk into a room and forget why. You feel anxious in a way you never used to, and a small voice asks: what is wrong with me?

Here is the most important thing to know first: nothing is wrong with you. If you're somewhere in your forties (or even your late thirties), what you're describing has a name. It's called perimenopause — the transition your body makes in the years before your periods stop for good. So many women reach this stage feeling blindsided, because no one explained it. Let's change that.

What perimenopause actually is

"Perimenopause" simply means around menopause. It's the stretch of time leading up to your final period, when your ovaries gradually wind down — but not in a smooth, tidy line. The Menopause Society describes it as the time before natural menopause, driven by "the ovaries' erratic production of hormones and less-frequent release of an egg." That word erratic is the key to almost everything you're feeling.

It helps to be clear on the words, because they get muddled all the time:

• Perimenopause is the transition — the symptomatic years while your hormones are shifting and your periods are still happening (even if irregularly).
• Menopause is a single point in time, defined as 12 consecutive months with no period. You only know you've reached it looking backwards.
• Postmenopause is everything after that.

So you can be deep in perimenopause for years while still having periods. That surprises a lot of people — they assume "menopause" is the whole experience, when really it's the finish line of a much longer journey.

The hormonal mechanism — why everything feels so unpredictable

For most of your adult life, your cycle ran on a fairly reliable rhythm: estrogen rises, you ovulate, progesterone rises, and if there's no pregnancy, both fall and you bleed. In perimenopause, the ovaries start running low on the egg-containing follicles that drive this rhythm — and the whole system gets noisy.

Three things are happening under the hood:

Estrogen fluctuates, then declines. This is the part people get wrong. Estrogen doesn't just glide gently downwards — early on it often swings wildly, sometimes spiking higher than in your younger years and then crashing. The large SWAN study (the Study of Women's Health Across the Nation, which followed over 3,000 women through this transition) found women don't share one tidy hormone curve at all — researchers identified several different estrogen patterns, including some that rise before they steeply decline. Those swings are why one week you feel fine and the next you're flattened.

Ovulation becomes erratic. As ovulation gets less frequent and less predictable, progesterone — which only really rises after you ovulate — often drops first. That shift in the estrogen-to-progesterone balance is part of why periods change and why sleep and mood can wobble.

FSH rises, but unevenly. FSH (follicle-stimulating hormone) is the signal your brain sends to nudge the ovaries into action. As the ovaries respond less, your brain shouts louder, so FSH trends upward over time. But — and this matters — a single FSH blood test on a single day can be misleading, because the level bounces around day to day. That's exactly why guidelines don't lean on it for most women (more on that below).

If you want to see this play out in your own body rather than just read about it, Petal's free Cycle Tracker lets you log every period, its length and flow, so the irregular pattern stops feeling random and starts becoming visible data — the kind of record that's genuinely useful when you talk to a clinician.

The timeline and stages, in plain language

Researchers have a formal map of this transition called STRAW+10 (the Stages of Reproductive Aging Workshop). You don't need the jargon, but the shape of it is reassuring because it shows there's a recognised pattern to the chaos:

• Late reproductive stage — cycles are still regular, but you may notice they're subtly shorter, or that the first signs of change are creeping in.
• Early perimenopause — your cycles start varying in length. STRAW+10 marks this as a persistent difference of 7 days or more between consecutive cycles. This is usually where the first hot flushes and sleep changes show up.
• Late perimenopause — you start having longer gaps with no period, defined as stretches of 60 days or more without bleeding. Symptoms often peak around here.
• Menopause — that 12-months-no-period milestone, after which you're postmenopausal.

Crucially, the SWAN researchers confirmed this staging works across women of very different backgrounds, body types and lifestyles. Your version won't look identical to your friend's or your mother's, but the underlying stages are shared.

How long does it last?

Longer than most people expect. The NHS notes perimenopause commonly begins in the mid-forties, with the average final period around age 51 — and the transition itself typically lasts about four years, though for some women it's a year or two and for others it stretches to a decade. Symptoms can also begin earlier, in the late thirties or early forties, for some women.

It's worth setting expectations honestly here, because one of the hardest parts is the open-endedness. This isn't a two-week event you grit your teeth through. It's a season of life — which is all the more reason to find what helps rather than just waiting it out.

The symptoms — and why they're so varied

Because the underlying driver is hormonal turbulence, symptoms ripple out into almost every system. Not everyone gets all of these, and severity varies enormously, but here are the common ones the major guidelines recognise.

Hot flushes and night sweats (vasomotor symptoms). The signature symptom — a sudden wave of heat, often with flushing and sweating, typically lasting one to five minutes. The Menopause Society notes up to 80% of women experience them. They're not trivial: SWAN found that among women with frequent flushes, the median total duration was 7.4 years, and they often persist for years after the final period. Knowing they can be this long-lasting is exactly why it's worth treating them rather than enduring them.

Sleep disruption. Sometimes it's night sweats waking you; sometimes it's lying awake with a racing mind even on a cool night. Poor sleep then amplifies everything else — mood, focus, appetite. Because sleep sits at the centre of so many other symptoms, it's one of the most useful things to track. Petal's Sleep Hub (a Petal+ feature) lets you log each night so you can actually see whether your worst days follow your worst nights — and bring that pattern to a doctor instead of a vague "I'm not sleeping well."

Mood changes. Irritability, low mood, tearfulness, and a new or heightened anxiety are all common. This isn't "all in your head" — the estrogen swings themselves are linked to mood vulnerability during this window. A quick daily mood note is one of the simplest ways to separate "a bad day" from a genuine pattern that deserves attention. Petal's free Mood Tracker is a 60-second daily check-in that maps how you feel against where you are in your cycle, so shifts you'd otherwise dismiss become visible over weeks.

Irregular periods. Usually the very first sign. Cycles may shorten, lengthen, get heavier or lighter, or skip entirely. Some variability is completely expected in this transition.

Brain fog. Forgetfulness, losing your thread mid-sentence, that "where are my keys again" feeling. It's a genuinely reported part of the transition for many women — and for most, it eases on the other side.

Genitourinary symptoms. Vaginal dryness, discomfort during sex, and more frequent urinary urgency or infections, caused by falling estrogen affecting these tissues. This one is widely under-discussed and very treatable — please don't suffer in silence with it.

What genuinely helps

Let's be honest and careful here, because this topic is full of overblown claims. Here's what the evidence actually supports.

Lifestyle foundations. Regular movement, limiting alcohol and caffeine (both can trigger flushes and wreck sleep), managing stress, and a balanced diet won't switch off perimenopause, but they meaningfully take the edge off symptoms and protect your longer-term heart and bone health. Because triggers are so individual, tracking is what turns vague advice into something personal. Petal's Nutrition Hub (Petal+) lets you log food and hydration alongside your symptoms, so if, say, your worst flushes cluster after wine or skipped meals, you'll spot the link rather than guess at it.

Effective medical options exist. This is important to say plainly: you do not have to white-knuckle through this. For hot flushes and night sweats, menopausal hormone therapy (often called HRT or MHT) is the most effective treatment, and NICE guidance explicitly recommends offering it to women with vasomotor symptoms associated with menopause. For those who can't or prefer not to use it, NICE points to menopause-specific cognitive behavioural therapy (CBT) as a recognised option, and there are non-hormonal medicines too. The right choice depends on your personal history and is a conversation to have with a clinician — but the headline is that real, evidence-backed help is available.

A quick word of caution on the flip side: be wary of unregulated supplements and "miracle" menopause products marketed online. Many are untested, and "natural" doesn't mean proven or safe. Stick to advice grounded in the major guidelines and your own doctor.

When to see a doctor

Perimenopause is a normal life stage, not an illness — but some symptoms still warrant a professional eye. NICE is clear that for most healthy women aged 45 or over, a doctor can identify perimenopause from your symptoms and cycle changes without blood tests. (FSH testing is generally only considered for women aged 40–45 with symptoms, or where menopause is suspected under 40.)

See a clinician if:

• Symptoms are disrupting your work, sleep, relationships or quality of life — you deserve support, and effective options exist.
• Your bleeding is very heavy, lasts a long time, happens between periods or after sex, or your cycles become very erratic in a way that worries you. Always get any bleeding after you've been period-free for 12 months checked promptly — that's outside the normal pattern.
• You're under 45 and your periods are changing or stopping.
• Low mood or anxiety is persistent or severe.

The single most useful thing you can do before that appointment is arrive with data instead of a foggy memory. That's where having logged your cycles, sleep and mood pays off — and Petal's free Personal Coach can help you pull the threads together into what's worth raising.

How Petal helps

• Perimenopause Coach (Petal+) — stage-aware symptom and mood guidance that shows you what's typical for your point in the transition, so confusing changes start to make sense in context.
• Sleep Hub (Petal+) — track each night and spot the patterns linking poor sleep to your hardest days, ready to share with a clinician.
• Nutrition Hub (Petal+) — log food and hydration against your symptoms to surface your personal triggers, from caffeine to skipped meals.
• Mood Tracker (free) — a 60-second daily check-in that maps your mood to your cycle, so emotional shifts become a visible pattern rather than a mystery.

This article is for information and isn't medical advice or a diagnosis. Perimenopause is highly individual — if your symptoms are affecting your life, or anything feels off, speak to a qualified clinician who can assess your personal situation.