Iron Deficiency in Women: New 2026 Guidelines, Symptoms and Why Your Iron Levels Matter

For many women, persistent fatigue, brain fog, dizziness and low energy have become so familiar that they are simply accepted as part of everyday life. Busy schedules, work, family responsibilities, menstrual cycles and hormonal changes can all take their toll. But what if these symptoms are more than just the result of a demanding lifestyle? Iron deficiency is a common yet frequently overlooked health issue, particularly among women. It can affect how we feel, think and function, sometimes long before it develops into anaemia.

In an important development, the American Society of Hematology (ASH) released updated clinical guidelines on 16 September 2026, recommending higher ferritin thresholds to help clinicians identify iron deficiency earlier and more accurately. The changes could make a meaningful difference for women whose symptoms have previously been dismissed or whose blood test results were considered normal. So, what has changed, what symptoms should women look out for, and what do the new guidelines mean for your health?

What is iron deficiency, and why does it matter?

Iron is an essential mineral that helps the body produce haemoglobin, the protein in red blood cells responsible for carrying oxygen around the body. Iron also supports muscle function, brain health and other important processes. When iron intake or absorption is insufficient, or the body loses too much iron, its iron stores gradually become depleted. This is known as iron deficiency. If the deficiency becomes severe enough to reduce haemoglobin levels, it can lead to iron-deficiency anaemia. However, iron deficiency can exist even when haemoglobin levels are still within the normal range. This distinction is important. A woman may have low iron stores and experience fatigue, reduced exercise tolerance or difficulty concentrating without being diagnosed with anaemia. If testing focuses only on haemoglobin, the underlying problem may be missed. According to ASH, iron deficiency is a major global health concern, affecting an estimated two billion people worldwide. Menstruating and pregnant individuals are among those at increased risk.

What has changed in the 2026 iron guidelines?

The new ASH guidelines aim to address inconsistencies in how iron deficiency is diagnosed. Previously, different thresholds were used in different settings, and some people with depleted iron stores may not have met the criteria for a diagnosis.

The updated recommendations use higher serum ferritin cut-offs, helping clinicians recognise iron deficiency in more people.

Ferritin is a protein that stores iron. A blood test measuring serum ferritin provides an indication of the body's iron reserves and is an important tool in assessing iron deficiency.

The updated ferritin thresholds

The ASH guidelines recommend the following diagnostic thresholds:

• Adults, including menstruating and pregnant individuals: ferritin of 30 ng/mL or lower

• Higher-risk groups: ferritin of 50 ng/mL or lower may be appropriate, including people with heavy menstrual bleeding and pregnant individuals with anaemia

• Adults with inflammation: ferritin below 100 ng/mL or transferrin saturation below 20% may indicate iron deficiency in the context of conditions such as inflammatory bowel disease, cancer or infection

• Children aged 9 months to 4 years: ferritin of 20 ng/mL or lower

  
  

One of the most significant changes is the recognition that a ferritin level previously considered acceptable may be low enough to indicate iron deficiency under the updated criteria. For example, a menstruating woman with a ferritin level of 25 ng/mL would meet the new ASH diagnostic threshold for iron deficiency, even if her haemoglobin remained normal. The key message is that iron deficiency deserves attention in its own right, rather than only after anaemia develops.

Why are women particularly affected by low iron?

Women experience several life stages and health circumstances that can increase their iron requirements or contribute to iron loss.

1. Heavy menstrual bleeding

Menstruation is one of the most common causes of iron loss in women of reproductive age. Women with heavy or prolonged periods may lose enough blood each month to gradually deplete their iron stores. Periods that last longer than usual, require frequent changes of menstrual products, involve flooding or large clots, or interfere with daily activities are worth discussing with a healthcare professional. Heavy bleeding should not simply be accepted as something women have to endure. It can contribute to iron deficiency and may also warrant investigation for an underlying gynaecological condition.

2. Pregnancy and the postpartum period

During pregnancy, the body's iron requirements increase to support the mother's expanding blood supply and the developing baby. Blood loss during childbirth can further reduce iron stores. Some women continue to experience iron deficiency after giving birth, particularly if their stores were already low during pregnancy or they experienced significant bleeding. Postpartum fatigue can easily be attributed to disrupted sleep and the demands of caring for a newborn. While these are genuine contributors, persistent exhaustion should not automatically be assumed to be part of new motherhood.

3. Dietary intake and absorption

Women who follow vegetarian or vegan diets can obtain iron from plant foods, including legumes, tofu, seeds and fortified cereals. However, iron from plant sources is generally less readily absorbed than iron from meat and seafood. A diet that contains insufficient iron, combined with increased requirements or blood loss, can increase the risk of deficiency. Some medical conditions, including coeliac disease and inflammatory bowel disease, can also affect iron absorption. Previous gastrointestinal surgery may be another contributing factor.

4. Perimenopause and changing menstrual patterns

During perimenopause, menstrual cycles can become irregular and bleeding may become heavier for some women. This can increase the risk of iron deficiency during a stage of life when symptoms such as fatigue, poor sleep and difficulty concentrating may already be occurring. Not every symptom during this transition is hormonal. It is worth considering other potential causes, including low iron, rather than attributing every change to perimenopause.

What are the symptoms of iron deficiency?

Iron deficiency can develop gradually, and symptoms vary from person to person. Some women notice significant changes in their wellbeing, while others experience few obvious symptoms until the deficiency becomes more pronounced.

Common symptoms include:

• Persistent fatigue or a lack of energy, even after adequate rest

• Brain fog, difficulty concentrating or reduced mental clarity

• Dizziness, light-headedness or headaches

• Shortness of breath during activity

• A racing or pounding heartbeat

• Reduced stamina or feeling unusually exhausted after exercise

• Pale skin

• Feeling cold more often than usual

• Hair shedding or brittle nails

• Restless legs, particularly at night

• Craving non-food substances or ice, a condition known as pica

  
  

These symptoms are not specific to iron deficiency. Thyroid disorders, sleep problems, vitamin deficiencies, stress and other medical conditions can cause similar experiences. However, when symptoms persist, especially in women with heavy periods, recent pregnancy or other risk factors, iron deficiency is an important possibility to discuss with a healthcare professional. You do not need to wait until you feel severely unwell before asking whether your iron levels should be checked.

How are iron levels tested?

If you suspect iron deficiency, speak with your GP about whether blood testing is appropriate. The tests your doctor recommends will depend on your symptoms, health history and risk factors.

Common tests include:

• Serum ferritin: Measures the body's stored iron and is central to the new ASH diagnostic guidance

• Full blood count (FBC or CBC): Measures haemoglobin and other blood cell parameters to check for anaemia

• Transferrin saturation (TSAT): Assesses how much of the iron-transport protein transferrin is carrying iron. This can be particularly useful when inflammation is present

• Other iron studies: Serum iron and total iron-binding capacity may help clarify the picture in selected cases

  
  

Ferritin needs to be interpreted carefully. It can rise during inflammation, infection and some chronic illnesses, potentially making iron stores appear more adequate than they are. This is why the ASH recommends considering both ferritin and transferrin saturation when evaluating adults with inflammation. It is also worth remembering that laboratory reference ranges are not necessarily the same as clinical diagnostic thresholds. A result marked as being within a laboratory's reference range does not automatically mean that iron deficiency has been ruled out. If your symptoms persist despite apparently normal results, ask your doctor to explain how your ferritin level has been interpreted and whether additional testing is appropriate.

What should women do if their ferritin is low?

Identifying iron deficiency is only the first step. The next is understanding why it has developed and deciding on the most appropriate treatment. Depending on the circumstances, treatment may involve oral iron supplements, intravenous iron or addressing an underlying cause of iron loss or poor absorption. Diet can also play a supportive role. Iron-rich foods include red meat, seafood, legumes, tofu, lentils, leafy green vegetables and iron-fortified cereals. Pairing plant-based iron sources with vitamin C-rich foods, such as citrus fruits, capsicum or berries, can improve iron absorption. However, diet alone may not be enough to correct an established deficiency, particularly when iron stores are significantly depleted or blood loss continues.

Avoid starting high-dose iron supplements without medical advice. Excess iron can be harmful, and supplements may cause side effects such as constipation, nausea and abdominal discomfort. Your doctor can help determine whether supplementation is necessary, which approach is appropriate and when your levels should be rechecked. Just as importantly, treatment should address the cause. For women with heavy menstrual bleeding, this may mean investigating and managing the bleeding itself. If iron deficiency is persistent or unexplained, further assessment for gastrointestinal blood loss, coeliac disease or another underlying condition may be needed. The goal is not simply to improve a number on a blood test. It is to restore iron stores, improve symptoms and reduce the likelihood of the deficiency returning.

What do the new guidelines mean for women in Australia?

The 2026 recommendations come from the American Society of Hematology, so they are not automatically a replacement for Australian clinical guidance or local laboratory protocols. Nevertheless, they provide an important evidence-based reference point for conversations between Australian women and their healthcare professionals. They also highlight why diagnostic thresholds should be considered alongside symptoms and individual risk factors. If you live in Australia and experience persistent fatigue, heavy periods, dizziness or reduced exercise tolerance, consider discussing an FBC and ferritin test with your GP. Depending on your circumstances, your doctor may recommend additional iron studies or investigations.

You could ask questions such as:

• Could iron deficiency explain any of my symptoms?

• Have my ferritin levels been assessed using an appropriate diagnostic threshold?

• Could heavy menstrual bleeding, pregnancy, diet or an absorption problem be contributing?

• Do I need further testing to identify the cause?

• If I need treatment, how will we monitor my response?

  
  

References

American Society of Hematology. (2026, September 16). ASH sets new standards for diagnosing iron deficiency. https://www.hematology.org/newsroom/press-releases/2026/ash-sets-new-standards-for-diagnosing-iron-deficiency 

American Society of Hematology. (2026). ASH guidelines on diagnosis of iron deficiency. https://www.hematology.org/education/clinicians/guidelines-and-quality-care/clinical-practice-guidelines/iron-deficiency-anemia/diagnosis-of-iron-deficiency American Society of Hematology. (n.d.). Iron-deficiency anemia. https://www.hematology.org/education/patients/anemia/iron-deficiency

Medical disclaimer: This article is for general educational purposes only and is not a substitute for personalised medical advice, diagnosis or treatment. The ASH thresholds discussed are diagnostic recommendations, not universal treatment targets. Individual results should be interpreted by a qualified healthcare professional in the context of symptoms, medical history and local clinical guidance.