Perimenopause: what it is, when it starts and how it feels

What's actually happening in perimenopause

Through your 20s and 30s, your ovaries run a fairly steady monthly rhythm: estrogen rises, you ovulate, progesterone rises, then both fall and you bleed. In perimenopause that rhythm gets wobbly before it winds down. The supply of eggs is running lower, ovulation happens some months and not others, and hormone levels swing more widely than before.

It isn't a smooth slide. Early on, estrogen can actually spike higher than it used to in some cycles, then crash. Progesterone tends to drop earlier and more steadily, because it's only made after ovulation. Those unpredictable swings, rather than simply low hormones, explain a lot of the symptoms: heavier periods one month, a skipped period the next, PMS that feels louder, and moods that change with less warning.

When it starts and how long it lasts

Cleveland Clinic puts the average length of perimenopause at about four years, though for some people it's a few months and for others it lasts up to ten. Menopause symptoms in general last around 7 to 9 years on average, according to the NHS. Menopause before 45 is called early menopause, and before 40 premature menopause; both are worth discussing with a doctor.

How perimenopause can feel

Everyone's version is different. Some people barely notice; others feel like their body has changed the rules overnight. The most common changes are:

• Periods: shorter or longer cycles, skipped periods, heavier or lighter bleeding. See periods in perimenopause.
• Hot flushes and night sweats: sudden waves of heat, often with a racing heart, that can wake you at night.
• Sleep: trouble falling asleep, or waking at 3 or 4 am and staying awake.
• Mood: more irritability, anxiety, teariness or low mood, sometimes out of nowhere. PMS can feel stronger.
• Brain fog: losing words, forgetting why you came into a room, finding it harder to focus.
• Body: joint aches, headaches, vaginal dryness, lower sex drive, needing to pee more often.

The full list is long, and we've gone through it in perimenopause symptoms.

Perimenopause and your mood

This part gets talked about least and often hits hardest. The brain has estrogen receptors in areas that regulate mood, sleep and temperature, so big hormone swings can affect how you feel as much as how you bleed. Research has found that the risk of depressive symptoms rises during the menopause transition, including in people who have never been depressed before, and people who had strong PMS or postnatal depression earlier in life may be more sensitive.

Seeing the pattern helps. When you know a flat or snappy week tends to arrive before a period, it's easier to plan for it and to explain it to a doctor. Read more on perimenopause mood swings.

Track the change, not just the dates

Lulu has a perimenopause mode for cycles that are starting to change. Log your period, symptoms and a one-tap daily mood, and you'll build the months-long record that makes conversations with your doctor easier.

What helps

• Talk to a doctor early. You don't have to wait for periods to stop. In the UK, NICE guidance says that over 45, perimenopause is usually diagnosed from symptoms alone, without blood tests.
• Know the treatment options. Hormone replacement therapy (HRT) is the most effective treatment for hot flushes and night sweats and can help mood and sleep. Non-hormonal medicines and CBT also have evidence. A doctor can weigh the benefits and risks for you.
• Protect your sleep. A cool bedroom, layers you can throw off, less alcohol and caffeine later in the day, and a steady wake time.
• Move and lift. Regular exercise helps mood and sleep, and strength training protects bones and muscles as estrogen falls.
• Check your iron if periods are heavy, and ask about treatment for heavy bleeding.
• Keep using contraception. You can still get pregnant. The NHS advises contraception for 2 years after your last period if you're under 50, or 1 year if you're 50 or over.

When to see a doctor