Iron deficiency: exploring links between levels and menstrual flow

It started with a simple hunch. On weeks when my period felt heavier, my energy seemed to drop in a way that coffee couldn’t fix. I caught myself asking, almost like a private science fair project, “Are my iron stores and my flow talking to each other?” The more I paid attention, the more I noticed a feedback loop: heavier bleeding can drain iron, and low iron can make the whole month feel like I’m running on reserve power. I wanted to write down what I learned—without hype, with room for uncertainty—so anyone else connecting these dots has a clear, kind starting place.

The feedback loop I kept missing

Here’s the pattern that finally clicked for me: heavy menstrual bleeding (HMB) commonly leads to iron deficiency, not usually the other way around. When a cycle is consistently heavy—needing to change protection every hour or two, flooding, passing clots, or periods stretching past seven days—that blood loss can slowly deplete iron stores. Over time, that can show up as fatigue, shortness of breath on stairs that used to be easy, headaches, or a pale look to the skin. Authoritative patient pages from women’s health organizations explain this clearly (for example, see ACOG on heavy menstrual bleeding), and it matches the lived experience many of us describe.

• What HMB looks like in real life: soaking through a pad or tampon every one to two hours for several consecutive hours; needing double protection; passing clots the size of a quarter or larger; having to get up at night to change protection regularly; or bleeding that lasts longer than a week.
• How low iron feels: tiredness beyond typical; lightheadedness; shortness of breath with usual activity; headaches; cold hands/feet; sometimes brittle nails or hair changes. (See accessible overviews at NHLBI and MedlinePlus.)
• The loop: more blood loss → lower iron stores → more symptoms between periods. Tackling both sides—flow and iron—usually makes the biggest difference.

Numbers that help me think straight

Lab numbers can feel abstract until you translate them into decisions. Two anchors helped me:

• Hemoglobin (Hgb) is a measure tied to anemia. The World Health Organization’s 2024 update keeps the nonpregnant adult female cutoff for anemia at about 12.0 g/dL, with graded severity below that (WHO guideline details here).
• Ferritin reflects iron stores. Many reputable sources consider ferritin below about 30 µg/L suggestive of iron deficiency, with lower values more specific for iron-deficiency anemia; interpretation always lives in context (see NIH ODS Iron Fact Sheet and MedlinePlus for plain-language guidance).

A few nuances I keep in mind so I don’t over- or under-react:

• Ferritin can rise with inflammation (for example during infections or chronic inflammatory conditions), which can mask low iron. Some clinical summaries note that a “normal” ferritin doesn’t fully rule out iron deficiency if there’s inflammation—context matters.
• Trends beat snapshots: a single ferritin or hemoglobin value is a moment in time; watching change after addressing heavy bleeding or after replenishing iron is more informative.
• Combinations guide action:
  • Low Hgb + low ferritin → iron-deficiency anemia likely; talk with a clinician about causes and treatment.
  • Normal Hgb + low ferritin → low iron stores without anemia; symptoms like fatigue may still improve when iron status is corrected.
  • Low Hgb + normal/high ferritin → think broadly (inflammation, other anemias) and ask for a thorough evaluation.

A simple way I track flow without obsessing

I didn’t want my life to become a spreadsheet, so I looked for a low-friction tool. The Pictorial Blood Loss Assessment Chart (PBAC) was that tool for me: you mark how soaked each pad/tampon was and add up a score. It’s not a diagnosis, but it helps measure patterns over months and gives something concrete to bring to a visit. There are printable PBACs shared for patients (for example, the Royal Children’s Hospital PDF guide) and reviews of how PBACs are used in research (see an open-access review here).

• I keep a small notepad in the bathroom drawer with a PBAC-style grid for cycle days 1–7.
• I add a quick note when I have “flooding” or need to change protection hourly.
• At the end of the month, I glance back to see whether my “heaviest two days” are stable, increasing, or improving.

Habits I’m testing between cycles

Self-experimenting doesn’t replace care, but it can make me a better partner in care. Here are the low-risk changes that felt realistic to try while staying within evidence-informed guardrails:

• Iron-smart meals: combining iron sources with vitamin C (citrus, tomatoes, peppers) to support absorption; spacing coffee/tea and calcium away from iron-rich meals or supplements. The NIH ODS fact sheet on iron summarizes how heme vs non-heme iron and meal composition influence absorption (NIH ODS).
• Routine check-ins: if I’ve had a few heavy cycles, I jot a reminder to ask for ferritin and a complete blood count next time I’m already getting labs for something else.
• Talking about flow-focused options: some treatments can lighten bleeding (for example, certain hormonal methods, or nonhormonal medicines like tranexamic acid or some NSAIDs during the heaviest days). I don’t self-prescribe; I bring my notes and questions to a clinician to discuss pros, cons, and fit (see causes and options in ACOG’s patient page).
• Repletion plan clarity: if iron is low, I ask about dose, form, and schedule—including whether alternate-day dosing might suit me, and how soon we should re-check labs to see if it’s working. General ferritin pages from MedlinePlus and Mayo Clinic helped me understand what “low” means and how repletion is monitored.

Signals that tell me to slow down and double-check

There are moments when my rule is “don’t overthink, just ask for help.” These are the ones I wrote on a sticky note:

• Soaking through one pad or tampon every hour for several hours, or needing to change at night repeatedly.
• Period > 7 days, or cycles so heavy they disrupt work/school regularly.
• Symptoms of anemia like chest discomfort, unusual shortness of breath, or dizziness that feels new or severe.
• New heavy bleeding after previously light cycles, especially if I’m over 40, postpartum, or have bleeding between periods.
• Family history of bleeding disorders, or bruising/bleeding that seems “too easy.” (Adolescent guidance from professional groups specifically recommends assessing for bleeding disorders when periods are heavy.)

Mini library I bookmarked for clarity

• ACOG Heavy Menstrual Bleeding
• NIH ODS Iron Fact Sheet (2025)
• MedlinePlus Ferritin Test
• WHO 2024 Hemoglobin Cutoffs
• PBAC Review (Open Access)

What I’m keeping and what I’m letting go

I’m keeping three principles on my bulletin board:

• Measure what matters: a few concrete notes (PBAC-style) tell a better story than my memory.
• Pair flow care with iron care: addressing only one side leaves me stuck in the loop.
• Use trusted guardrails: when I see anemia-level hemoglobin or consistently low ferritin, I use that as a signal to involve a clinician and to ask about causes and options—not to panic, and not to self-dose blindly.

On the flip side, I’m letting go of the idea that feeling worn out is just “busy life.” Sometimes, it’s biochemistry. And that’s something we can work with.

FAQ

1) Can low iron make periods heavier?
Answer: Usually the direction runs the other way—heavy periods often lead to low iron. That said, low iron can worsen fatigue and recovery between cycles, which can make heavy flow feel even harder to tolerate. If bleeding is heavy, it’s reasonable to check iron status and address both issues together (see ACOG’s overview of heavy bleeding and iron deficiency).

2) What ferritin level is considered “low” if I have heavy periods?
Answer: Many references suggest ferritin below about 30 µg/L indicates low iron stores, but interpretation depends on your whole picture and whether inflammation is present. A clinician may also look at hemoglobin and other iron studies to get the full story (see NIH ODS and MedlinePlus ferritin pages).

3) How long does it take to feel better once iron is replaced?
Answer: It varies. Some people notice more energy within a few weeks of an effective plan, while full replenishment of iron stores can take a few months. Follow-up labs help confirm progress and adjust the approach. It’s important to also address ongoing heavy bleeding so you’re not pouring from an empty cup.

4) Do I need to track my blood loss precisely?
Answer: Not perfectly. A simple PBAC-style tally for a few cycles is often enough to show patterns and guide a discussion. It’s far more helpful than trying to estimate milliliters and feeling unsure. Printable charts and research summaries are available if you like structure.

5) I eat little or no meat. Can diet alone fix low iron?
Answer: Many people meet iron needs with plant-forward diets, especially when they pair non-heme iron sources (beans, lentils, spinach, fortified grains) with vitamin C–rich foods and pay attention to timing with coffee/tea/calcium. If iron is already low, diet plus an evidence-based repletion plan may be recommended—ask about the options and monitoring.

Sources & References

• ACOG — Heavy Menstrual Bleeding (Patient Page)
• NIH ODS — Iron Fact Sheet (2025)
• MedlinePlus — Ferritin Blood Test (2025)
• WHO — Haemoglobin Cutoffs to Define Anaemia (2024)
• An Open-Access Review of PBAC Methods (2020)

This blog is a personal journal and for general information only. It is not a substitute for professional medical advice, diagnosis, or treatment, and it does not create a doctor–patient relationship. Always seek the advice of a licensed clinician for questions about your health. If you may be experiencing an emergency, call your local emergency number immediately (e.g., 911 [US], 119).