A woman comes in exhausted. Not tired — exhausted. Climbing a flight of stairs leaves her winded in a way it didn't two years ago. She's foggy by mid-afternoon. Her hair is coming out more than it used to. She's been told it's stress, or perimenopause generally, or that she should try getting to bed earlier.
Somewhere in the conversation I'll ask about her periods, and she'll say — almost as an aside, because nobody has ever connected the two — that they've become much heavier over the last few years.
Those are not two separate problems. Very often they are one problem, and it's one that a single blood test can point to.
Why bleeding changes in perimenopause
In a typical cycle, estrogen builds the uterine lining and progesterone stabilises it. The two work as a pair.
In perimenopause, that pairing comes apart. Ovulation becomes less consistent, and progesterone is only produced in meaningful amounts after ovulation. So you can end up with cycles where estrogen is doing its job — sometimes surging higher than it used to — with far less progesterone to balance it.
The result is a lining that builds up more than usual with less to hold it steady. When it sheds, there's simply more to shed.
This is why so many women describe periods that are heavier, longer, more clotted, or unpredictably spaced in their forties. It isn't random, and it isn't a sign that something has gone wrong with you. It's a predictable consequence of how the hormonal partnership changes.
Where the exhaustion comes from
Every period costs iron. A heavier period costs more.
When losses outpace what you're taking in, your iron stores draw down gradually. The word "gradually" is doing a lot of work there, because it's the reason this goes unnoticed for so long. Nobody wakes up depleted. It happens across months and years, and you adapt to each small decrement without registering it.
What it can look like: fatigue that sleep doesn't resolve, breathlessness on mild exertion, poor exercise tolerance, brain fog, hair shedding, brittle nails, cold hands and feet, restless legs at night, and — in some women — a strange urge to chew ice.
Every one of those symptoms sits comfortably inside the story of "you're in perimenopause, this is what it feels like." That overlap is precisely why it gets missed.
Depleted stores and low haemoglobin aren't the same thing
This is the part I most want women to walk away understanding.
A standard blood count measures haemoglobin — whether you're anaemic. But your body holds a reserve of stored iron, and it will draw that reserve down substantially before haemoglobin falls out of range.
Which means you can be running on very low stores, feeling every symptom above, and be told your blood count is normal. Because it is. It's measuring the wrong thing for the question you're asking.
The measure that reflects stored iron is ferritin, and it is not always included in routine bloodwork. If you have heavier periods and unexplained fatigue, it's a reasonable thing to ask about specifically.
I'd add one honest caveat: ferritin can be pushed up by inflammation, so it's read alongside other markers and in the context of your actual symptoms rather than in isolation. Which is a version of the same point I make about every lab — the number means something only when someone reads it against you.
What to ask for
Bring specifics. "Heavy" is subjective and lands weakly in a short appointment. These land better:
- How many days you bleed, and how many of those are heavy
- Whether you're changing protection more often than every two hours on your heaviest days
- Whether you're passing clots, and roughly what size
- Whether you're flooding through onto clothing or bedding
- Whether bleeding limits what you'll do — work, exercise, travel, plans
Then a sentence like: "My periods have got significantly heavier over the last few years and I'm exhausted. Can we check my iron stores, including ferritin?"
That names the pattern, names the test, and takes about eight seconds.
Two things I won't do here
I won't tell you to start an iron supplement. Iron is one of the few nutrients where taking it when you don't need it causes real problems, the right form and amount vary considerably between people, and it interacts with other things you may be taking. That decision follows testing — not an article.
And I won't tell you heavy bleeding is always hormonal. It very often is. But fibroids, polyps, thyroid dysfunction, and clotting differences all cause heavy bleeding too, and some of them are straightforward to identify once someone looks. That's the point of a proper workup: not to assume it's perimenopause, but to find out.
When bleeding needs prompt attention
Most heavy bleeding in perimenopause is manageable and not dangerous. Some warrants a prompt appointment rather than waiting:
- Soaking through protection hourly for several consecutive hours
- Bleeding that lasts longer than seven days
- Bleeding between periods, or after intimacy
- Any bleeding at all after twelve full months without a period. This one is not a wait-and-see. It's common for it to turn out to be nothing serious, and it should always be assessed promptly.
- Symptoms of significant blood loss — dizziness on standing, a racing heart, breathlessness at rest
The point
If your periods have changed and you're worn out, please stop treating those as two separate complaints filed under "getting older."
They're frequently the same story, and it's a story with a test attached. You may not need anything complicated. You may just need someone to check the thing nobody has checked.
You deserve to feel informed, in control, and empowered — not dismissed or defeated.
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This article is for educational purposes and is not a substitute for individual medical advice, diagnosis, or treatment. Do not begin iron supplementation without testing and guidance from a qualified healthcare provider.