How heavy is too heavy, and what to do about it

Heavy periods are one of the most under-reported problems in medicine, for a simple structural reason: nobody can see anyone else's. You calibrate against a sample size of one and assume you are ordinary.

A significant number of people bleed enough to become anaemic and never mention it, because they assume everyone bleeds like that.

The definition puts you at the centre

The old clinical threshold was 80ml of blood loss per cycle. It is still cited, and it is essentially unusable — nobody measures.

Current guidance in the UK and elsewhere defines heavy menstrual bleeding as excessive bleeding that interferes with a person's physical, social, emotional or material quality of life. That is a deliberate change. It means you do not have to prove a volume to be taken seriously; the impact is the criterion.

The practical markers

Clinicians ask about these because they correlate reasonably well with actual blood loss:

• Soaking through a pad or tampon every hour or two for several consecutive hours
• Needing to use a pad and a tampon together
• Getting up at night to change protection
• Passing clots larger than a 10p coin or a US quarter
• Bleeding lasting more than seven days
• Flooding — bleeding through onto clothes or bedding
• Organising your life around your period: choosing what to wear, avoiding plans, keeping spare clothes at work

Any one of those is worth a conversation. Several of them together makes it much more than worth it.

The tiredness question is separate and important. Heavy periods are the most common cause of iron deficiency in menstruating people, and the fatigue, breathlessness on stairs, brain fog and low mood that come with low iron are frequently attributed to stress or poor sleep for years. Iron deficiency in women is worth reading alongside this; so is low ferritin and low mood, because you can be iron-deficient with a completely normal full blood count.

What is usually behind it

Fibroids. Benign muscular growths in or on the uterus. Very common, more common and often more severe in Black women, and frequently symptomless — but fibroids that distort the uterine cavity cause substantial bleeding. Ultrasound finds them easily.

Adenomyosis. Endometrial-type tissue growing into the muscular wall of the uterus. Classically causes heavy and painful periods with a bulky, tender uterus. Historically under-diagnosed because it needs imaging to see and was long thought to require a hysterectomy to confirm.

Polyps. Small benign growths in the lining. Often cause bleeding between periods as well.

Hormonal patterns without ovulation. Cycles where ovulation does not occur produce no progesterone, so the lining builds under unopposed oestrogen and eventually sheds unpredictably and heavily. Common in perimenopause and in PCOS.

Bleeding disorders. Von Willebrand disease is the one that matters here. It affects roughly 1% of people, it is inherited, and heavy periods from the very first one — plus easy bruising, nosebleeds or heavy bleeding after dental work — is the classic presentation. It is badly under-diagnosed in women, who often get told for a decade that their periods are just heavy.

Thyroid disease. Both under- and over-active thyroid change bleeding patterns, and a thyroid panel is a cheap thing to check.

Copper coils increase bleeding for many people, particularly in the first months.

And in people over about 45, or anyone with bleeding between periods or after sex, the assessment also has to exclude endometrial pathology. That is routine, not alarming.

What a good assessment looks like

A full blood count and ferritin — not just haemoglobin, because ferritin falls long before haemoglobin does. Thyroid function. A pelvic ultrasound. Coagulation screening if the history suggests it. An examination.

If you leave with a prescription and no tests, that is worth pushing back on politely. How to prepare for a ten-minute appointment has the specific framing that tends to work.

Treatment is broader than most people are offered

Options include tranexamic acid taken only during bleeding, which reduces loss substantially and is not hormonal; NSAIDs, which reduce both bleeding and pain; the hormonal coil, which is first-line in several guidelines and often reduces bleeding dramatically; combined hormonal contraception; and, for structural causes, procedures ranging from polyp removal to fibroid embolisation to ablation.

The point is that "heavy periods" is not one condition with one answer, and being offered a single option is not the same as having a single option.

Bring a record

The most useful thing you can walk in with is a few months of actual data: how many days you bled, how many products you used on the heaviest days, whether you flooded, how tired you were in the following week. Written down at the time, not recalled.

That record is also what makes the connection visible between your period and the fortnight afterwards — the specific reason Naked logs symptoms, energy and mood against your cycle rather than treating bleeding as an isolated event. Plenty of people discover their worst-energy week is the one after their heaviest period, which points straight at iron and changes what they ask for.