If you're in your 40s and your periods have started behaving differently — shorter cycles, occasional skipped months, or a flow that's suddenly heavier or lighter than you're used to — this is usually perimenopause, the transition phase before menopause. It's a normal stage, not a problem to fix, but it's worth understanding what's normal within it and what deserves a check.
The period changes that typically signal perimenopause
Perimenopause is defined by change, not by any single symptom. The most common patterns:
- Shorter cycles. Periods arriving a few days earlier than your usual rhythm, cycle after cycle.
- Skipped months. Occasional months where a period doesn't come at all, then resumes.
- Flow changes. Periods that become noticeably heavier or lighter than what was typical for you for years.
- Longer gaps as it progresses. As perimenopause continues, the gaps between periods generally stretch out further, eventually leading to menopause (12 months with no period at all).
Other common signs alongside the period changes
Perimenopause is a hormonal transition, so period changes often show up alongside:
- Hot flushes or sudden warmth
- Disrupted sleep
- Mood changes
- Vaginal dryness
None of these need to all be present — perimenopause looks different from woman to woman.
When it's worth testing hormones — and when it's not
For most women in their 40s with the pattern described above, perimenopause is a clinical diagnosis based on your age and your symptom pattern — a blood test isn't usually needed to confirm it. Testing FSH or AMH is more useful in specific situations: if your periods have changed unusually early (well before 40), or if the picture is unclear and your doctor wants to rule out another cause. Don't assume a test is required just because the word "hormone" is involved — ask your doctor whether it would actually change anything about your care before requesting one.
What still needs a doctor's visit, not just "it's perimenopause"
Perimenopause explains a lot, but it shouldn't be used to explain away everything. See your doctor rather than assuming if you notice:
- Bleeding that's unusually heavy, with large clots, or soaking through protection quickly
- Bleeding between periods, not just irregular timing of the periods themselves
- Any bleeding after sex
- Periods so frequent they're essentially continuous
These patterns deserve a proper look, even during a time when "irregular" is expected.
Frequently asked
At what age does perimenopause usually start?
It typically begins in the 40s, though the exact timing varies widely between women. Changes well before 40 are less typical and worth mentioning to your doctor.
How long does perimenopause last?
It varies, but it commonly spans several years before periods stop altogether at menopause. The pattern usually shifts gradually rather than all at once.
Do I need a blood test to confirm I'm in perimenopause?
Not usually. For most women in their 40s with a typical symptom pattern, your doctor can identify perimenopause from your age and history alone. Testing is reserved for atypical or unclear cases.
Is heavy bleeding just part of perimenopause?
Some flow change is expected, but unusually heavy bleeding, clots, or bleeding between periods should still be checked rather than assumed to be routine perimenopause — these can have other causes that are worth ruling out.