Perimenopause

Early signs of perimenopause, and a checklist to track them

Perimenopause rarely starts with a hot flash. More often it starts with a cycle that runs a few days short, a night you wake and can't get back to sleep, or a month where your mood feels unfamiliar. Here is what to watch and how to write it down.

Sources checked October 30, 2026

A woman in her fifties in a white shirt cooling herself with a paper fan, smiling
The short answer

The earliest sign is usually a change in your periods: they come more or less often, and bleeding gets heavier or lighter.[1] Hot flashes, night sweats, sleep problems, mood changes and brain fog are common too.[1][2]

A dated log of periods and symptoms over 2 or 3 months is a useful thing to take to a doctor, because for women 45 and over the diagnosis rests on symptoms and periods, not a blood test.[4]

Your cycle usually changes first

The Menopause Society describes the order: at first, cycles often get a little shorter than usual and the number of bleeding days changes. As perimenopause goes on, cycle length can vary by 7 days or more, and in the late transition you can go 60 days or more between periods.[2]

That's why period dates matter so much here. The Menopause Society suggests tracking bleeding on a calendar or an app so a clinician can review it.[2] 3 cycles in a row, with the lengths written down, are easier to compare than one odd month.

The checklist

Tick what you notice, and note the date. These come from the NHS symptom list; you won't have all of them, and they can change over the years.[1]

SignWhat to note
Cycle length changesFirst day of each period; the app counts the days between
Heavier or lighter flowFlow on each day, and any spotting between periods
Hot flashesTime of day and how strong, from mild to severe
Night sweatsWhich nights, and whether they woke you
SleepBedtime, wake-ups, how rested you felt
MoodLow, anxious or irritable days, and where they fall in your cycle
Brain fogDays with trouble concentrating or finding words
AchesJoint pain, muscle aches, headaches
Vaginal drynessDiscomfort, and whether it affects sex

How long should I track before seeing a doctor?

2 or 3 cycles let you compare one cycle length with the next. If symptoms are making daily life hard, go sooner and bring whatever you have: even 2 weeks of dated hot flashes helps.

See a doctor without waiting for a pattern if you have:[1][3]

  • heavy bleeding, or bleeding that's heavier or lasts more days than usual
  • bleeding after sex or between periods
  • any bleeding after 12 months with no period

Periods that start less than 21 days apart count as irregular on the NHS definition, so bring those dates to your next visit.[5]

Why there is no simple test

In perimenopause the ovaries make hormones erratically,[2] so one blood test is a snapshot of one day. NICE in the UK tells doctors to identify perimenopause in otherwise healthy women aged 45 or over from their symptoms and periods, without lab tests. Between 40 and 45 it says a doctor may consider an FSH blood test, and under 40 separate guidance on premature ovarian insufficiency applies, which does use blood tests.[4]

Putting it on one page

Her Good Days keeps the dates for you. In perimenopause the Log button puts Hot flash, Period, Sleep, Mood and Brain fog first, and the doctor report turns a month of entries into a few pages: cycle lengths, symptom counts by week, and sleep next to night sweats. The app never tells you what stage you're in. You choose it, and you can change it.

The Log menu for Karen, 47, in perimenopause: Again, Brain fog at 8:30 AM on top, then Hot flash, Period, Sleep, Mood and Brain fog
Karen's Log menu: Hot flash, Period, Sleep, Mood, Brain fog.

For the bigger picture of this stage, see perimenopause in Her Good Days.

Questions

What are the first signs of perimenopause?

The NHS says one of the first signs is usually a change to your periods: they come more or less often, and bleeding gets heavier or lighter. Hot flashes, night sweats and sleep problems are also common.

Is there a test for perimenopause?

Usually not. Hormone production is erratic in this stage, and UK guidance (NICE) tells doctors to identify perimenopause in women 45 or over from their symptoms and periods, without lab tests.

How long does perimenopause last?

It varies a lot. ACOG puts perimenopause at roughly ages 45 to 55, and the NHS says symptoms usually last 7 to 9 years, sometimes longer. Menopause is dated once you've gone 12 months with no period.

Can I still get pregnant in perimenopause?

Yes, even with irregular periods. The NHS advises contraception until 1 year after your final period if you're 50 or over, and 2 years if you're 40 to 49. Your doctor can help you choose.

Start with today

Free on iPhone and Android.