If you are 40 and wondering whether this is perimenopause, the short answer is that it very well might be, and you are not too young.
The longer answer matters, because 40 sits at a point where the medical response should be different from 50.
The arithmetic
The average age of the final period in Australia is 51 to 52.
Perimenopause commonly runs four to ten years before that.
So symptoms beginning at 41 or 42 are entirely ordinary. Beginning in the late thirties is less common but well within normal.
Yet "you're too young for that" remains one of the most frequently reported responses women get at this age.
What is normal at 40
Cycle changes. Often the first sign. Watch for variability rather than direction — a difference of seven days or more between consecutive cycles. Cycles frequently shorten before they lengthen.
Heavier periods. Cycles without ovulation allow the lining to build more than usual. Common, and worth mentioning because of iron.
Sleep disruption. Particularly waking in the small hours.
Mood change. Anxiety, irritability, or a flatness that feels out of character.
Physical symptoms. Joint aches, headaches changing in pattern, heart racing.
Hot flushes. Often later than people expect. Their absence proves nothing.
What is not routine at 40
This is where the age matters.
Periods stopping altogether. Before 45 this is early menopause. Before 40 it is premature ovarian insufficiency, which affects about 1 in 100 women.
Both warrant prompt assessment rather than watchful waiting, because the long-term considerations around bone and cardiovascular health are different from menopause at the average age.
Very heavy bleeding, bleeding between periods, or bleeding after sex. These need assessment at any age.
See early menopause and premature ovarian insufficiency if your periods have stopped or become markedly irregular.
Why testing is different under 45
For women over 45, Australian guidance is that perimenopause is diagnosed from symptoms and cycle pattern. Bloods add little, because levels swing so much that one day's reading can look normal.
Under 45, the question being asked is different. A doctor is distinguishing ordinary perimenopause from early menopause, and excluding other causes.
So testing has a genuine role here — typically the hormones that signal to the ovaries, often repeated some weeks apart, alongside thyroid function and a pregnancy test.
If you are 40 with significant symptoms and a doctor declines to investigate at all, that is worth a second opinion.
Things that get missed at this age
Iron deficiency. Heavier perimenopausal periods are the most common cause in women, and depleted iron produces exhaustion, palpitations, poor concentration and hair loss. Ask for ferritin specifically, not just a full blood count.
Thyroid problems. More common with age and in women, and they produce an almost identical symptom picture.
Contraception. The assumption that fertility has gone catches people out. Ovulation becomes unpredictable, not absent. Unplanned pregnancy in the mid-forties is more common than most people assume.
The part nobody warns you about
At 40 you are often in the densest part of life. Young children or teenagers. Career at full tilt. Parents starting to need help.
Symptoms land on top of that, and the natural conclusion is that you are simply overloaded. Sometimes that is true. Often it is both, and the hormonal half goes unexamined for years.
The distinguishing question is whether physical symptoms are present. Stress does not cause night sweats or change your cycle.
Perimenopause or burnout? covers that separation in detail.
What to do
- Track your cycle for two or three months — dates, length, how heavy
- List symptoms with rough start dates, and what they are stopping you doing
- Book a long appointment and say it is to discuss perimenopause
- Ask for bloods — thyroid, full blood count, ferritin, vitamin D, B12
- Ask directly what else is worth excluding
Our symptom check assembles the record in about two minutes.