She is 44. Her periods still arrive every 28 days, give or take. But they are heavier than they were, she is waking at three most nights, and twice last month she went hot at her desk for no reason at all.
Her GP checked her cycle length, found it regular, and said she was too young and too regular to be perimenopausal. Come back when things change.
Research published in 2026 suggests she was already in it, and that the rule she was measured against is the problem.
Menopause staging runs on something called STRAW+10, agreed in 2011 and used worldwide. It defines where you are primarily by your menstrual cycle.
Early perimenopause is marked by a persistent difference of seven days or more between consecutive cycles. Late perimenopause begins when you skip 60 days or more.
It is a sensible system, and it has one structural weakness: it measures the calendar, not the biology. A woman whose hormones have started shifting but whose cycle length has not yet changed is classified as premenopausal.
An international study published in Menopause examined which symptoms actually distinguish perimenopausal women from premenopausal ones. Not which are most common, which are most specific.
Two stood out.
Moderate to severe hot flushes and night sweats were nearly five times more prevalent in perimenopause than premenopause.
Vaginal dryness occurred 2.5 times more often, making it a highly specific indicator.
And two failed to distinguish anything. Low mood and memory concerns, the symptoms women most often report and most often blame themselves for, were far less discriminative. They are common in perimenopause and common outside it, so on their own they tell you very little.
The researchers then looked at women with regular cycles who reported changes in flow alongside hot flushes.
Those women showed physiological patterns consistent with early perimenopause, despite being classified as premenopausal under STRAW+10.
In other words: the biology had started, the calendar had not caught up, and the diagnostic framework was reading the calendar.
The conclusion drawn was that symptom-first cues, particularly vasomotor symptoms and vaginal dryness, may identify the transition earlier and more accurately than cycle length alone.
The practical consequence is the conversation described at the top of this article, repeated in surgeries every day.
A woman reports symptoms. Her cycles are checked. They are regular. She is told she is too young or too regular, and asked to come back when her periods change.
Meanwhile her sleep is broken, her anxiety has climbed, and sex has become uncomfortable. Those symptoms are treatable now.
There is a second problem underneath. Because mood and memory symptoms are non-specific, they get attributed to stress, work or the children, and women frequently accept that explanation. Some are prescribed antidepressants for what is a hormonal transition, which is a recognised pattern rather than an occasional error.
Given that flushes and vaginal dryness carry the diagnostic weight, those are what to lead with.
Report vasomotor symptoms precisely. Not "I get warm sometimes" but how often, how severe, and whether they wake you. Moderate to severe symptoms are the discriminating ones.
Mention vaginal dryness. Women skip this, and it is one of the two most specific signals available. If sex has become uncomfortable or you feel dry day to day, that is diagnostic information rather than an embarrassment.
Describe changes in flow, not just timing. Heavier, lighter, more clots, shorter bleeds. The 2026 work suggests flow changes matter even when cycle length has not moved.
Track two or three cycles properly before the appointment. Vague reports get absorbed into normal; specific ones do not.
The first signs of perimenopause covers the full symptom picture, and the free menopause stage quiz gives you a structured result to take with you.
The obvious response is to ask for hormone testing. It rarely helps, and it is worth understanding why.
In perimenopause, oestrogen and FSH swing unpredictably within a single cycle and between cycles. A test taken on a high day looks premenopausal; the same woman tested a fortnight later might look postmenopausal.
This is why NICE and most guidelines advise against routine hormone testing for women over 45 with typical symptoms. Symptoms guide the diagnosis because they are more stable than the numbers.
Under 45, testing has more value, mainly to exclude other causes and to identify premature ovarian insufficiency, which is a different situation requiring different management. Should you test your hormones? covers when it is worth it.
Before settling on perimenopause, two conditions produce an almost identical picture and are settled by cheap tests.
Thyroid dysfunction. Fatigue, weight change, low mood, sleep disruption, irregular periods. Ask for TSH with free T4 and free T3 rather than TSH alone.
Iron deficiency. If bleeding has become heavier, ferritin is likely falling, and that explains a great deal of the exhaustion. Ferritin can be depleted long before anaemia appears on a full blood count.
Both are worth excluding, and both are frequently missed because the symptoms fit the perimenopause story so neatly. Thyroid or hormones? covers the overlap.
Perimenopause does not begin when your periods become irregular. It begins when your hormones start fluctuating, and that can be several years earlier.
The framework used to stage it measures cycle length, which is a reasonable proxy and a lagging one. The 2026 evidence suggests hot flushes and vaginal dryness identify the transition earlier and more reliably.
So if you are forty-four with regular periods, night sweats and a change in flow, you are not too young and you are not imagining it. You are ahead of the diagnostic criteria, which is a different thing entirely.
Can I be in perimenopause with regular periods?
Yes. The 2026 research found women with regular cycles but changes in flow plus hot flushes showed physiological patterns consistent with early perimenopause, despite being classified as premenopausal by the standard criteria.
Which symptoms actually indicate perimenopause?
Moderate to severe hot flushes and night sweats, nearly five times more prevalent than in premenopause, and vaginal dryness, 2.5 times more common. Low mood and memory concerns are far less specific.
Why did my doctor say I am too young?
Because the standard staging framework defines perimenopause primarily by changes in cycle length. If your cycles are still regular, you fall outside the definition even when your hormones have already started shifting.
Should I ask for a blood test?
Over 45 with typical symptoms, generally no. Hormone levels swing too much in perimenopause for one sample to be meaningful, which is why guidelines advise against routine testing. Under 45 it has more value.
What should I say at the appointment?
Lead with hot flushes and vaginal dryness, since those carry the diagnostic weight. Describe frequency and severity, mention changes in flow rather than only timing, and bring two or three tracked cycles.
How long does perimenopause last?
Typically four to eight years before the final period, though it varies considerably. Menopause itself is confirmed only in retrospect, after twelve consecutive months without a period.
What else should be ruled out?
Thyroid dysfunction and iron deficiency both mimic perimenopause closely and are settled by inexpensive tests. Ask for TSH with free T4 and free T3, and ferritin if bleeding has been heavy.
Sources: International differences exist in knowledge gaps and most common perimenopause symptoms, Menopause 2026 · Harlow SD et al., Executive summary of the Stages of Reproductive Aging Workshop +10, J Clin Endocrinol Metab 2012;97(4):1159-68 · NICE guideline NG23, Menopause: diagnosis and management · Educational only, not medical advice.
Keep reading: The first signs of perimenopause · Perimenopause vs menopause · Should you test your hormones? · Thyroid or hormones? · Free menopause stage quiz · Take the free Hormone Quiz