Iron deficiency in women

Why it is so common

Women are particularly vulnerable to iron deficiency for reasons related to biology, life stage and diet patterns.

Periods lose iron

Every period costs you iron. A typical period loses 30 to 40 mg of iron. Heavy periods lose substantially more. Over years and decades this adds up. Women with heavy menstrual bleeding are at particular risk of iron deficiency. The problem is mostly invisible until you measure it. Many women have lived with low iron for years without realising.

Pregnancy increases demand

Pregnancy roughly doubles iron requirements. Your blood volume expands. The growing baby and placenta need iron. Most women cannot meet the increased demand from diet alone and many become iron deficient during pregnancy or in the months after birth. NHS antenatal care includes iron testing for this reason.

Dietary patterns

Plant based diets contain iron but in a form that is less absorbed than the iron in red meat. Women who eat little or no red meat are at higher risk if they do not deliberately compensate. Tea and coffee with meals reduce iron absorption. Calcium supplements taken with iron rich meals reduce absorption. These small things add up.

Other contributors

Coeliac disease, inflammatory bowel disease and other gut conditions reduce iron absorption. Frequent blood donation depletes iron. Certain medications affect absorption or use. Endurance training can produce iron loss through several mechanisms. Iron deficiency can have several contributing factors at once.

The symptoms to know

Iron deficiency symptoms are often vague and easily attributed to other things. Knowing the pattern helps catch it earlier.

Fatigue beyond what you expect

The classic symptom. Tiredness that does not match what you have been doing. Sleeping enough but waking up tired. Energy that crashes through the day. Feeling exhausted by previously manageable activities. The fatigue of iron deficiency is real and physiological. It is not in your head. It is not just because you are busy.

Breathlessness with effort

Climbing stairs leaves you breathless when it never used to. Walking briskly feels harder. Exercise that was comfortable now feels like work. The breathlessness is because your blood is not carrying enough oxygen due to low haemoglobin. Iron is needed to make haemoglobin. Low iron means less oxygen delivery to muscles.

Brain fog and mood

Difficulty concentrating, word finding problems, low mood and irritability all come with iron deficiency. The brain needs oxygen too and shortage shows up cognitively. Many women blame themselves for not thinking clearly when the actual cause is low iron. The improvement when iron is corrected can be striking.

Other signs

Hair shedding more than usual. Brittle nails sometimes with a characteristic spoon shape. Dizziness or feeling light headed when standing up. Cold hands and feet. Restless legs at night. Cravings for ice or strange non food items. Pale skin and pale inner eyelids. Frequent infections. These are all on the iron deficiency picture though no one woman has all of them.

How to find out

Iron status is diagnosed through blood tests. Knowing what to ask for helps you get the right tests and the right interpretation.

The tests that matter

Full blood count shows whether you have anaemia (low haemoglobin). Ferritin shows your iron stores, which deplete before anaemia develops. Many women have low ferritin without yet being anaemic. Symptoms can be significant at this stage. The combination of full blood count plus ferritin gives the most useful picture.

What the numbers mean

Ferritin below 30 ng/ml suggests iron deficiency even when the rest of the blood count looks normal. Some clinicians use cut offs as high as 50 ng/ml for symptomatic women. The standard NHS normal range is wider than the optimal range for symptom free function. Ferritin in the bottom of the normal range with symptoms is worth treating in many women.

Asking your GP

If you have symptoms suggesting iron deficiency, ask your GP for a full blood count plus ferritin. Some practices test ferritin routinely with full blood count. Others do not unless asked. Explaining your symptoms helps get the right tests. If your ferritin is borderline and you have symptoms, push for a trial of iron supplementation.

When to investigate further

Iron deficiency without an obvious cause warrants investigation. If you do not have heavy periods, are not pregnant and have no other obvious explanation, your GP may want to check for hidden bleeding or absorption problems. This is particularly important in post menopausal women where heavy periods are no longer in the picture. Sudden iron deficiency in older women warrants prompt assessment.

Getting your iron back up

Iron deficiency responds well to treatment. The trick is being thorough and patient. Quick fixes rarely work as quickly as people want.

Iron supplements

Standard treatment is iron tablets, typically ferrous sulphate, ferrous fumarate or ferrous gluconate at doses providing 100 to 200 mg of elemental iron daily. Side effects including digestive upset and constipation are common. Alternate day dosing produces better absorption than daily dosing in some research and reduces side effects. Speak to your GP about what suits you.

Diet contributions

Red meat is the most concentrated dietary source. Liver is particularly rich. Plant sources include pulses, dark green vegetables and fortified cereals though iron from these sources is less absorbed. Vitamin C improves absorption from plant sources, so eating fruit or vegetables alongside helps. Tea, coffee and calcium reduce absorption and should be taken away from iron rich meals or supplements.

How long it takes

Haemoglobin starts to recover within weeks of starting iron. Full replenishment of iron stores takes 3 to 6 months. Stopping supplements too early is a common cause of relapse. Symptom improvement often appears within 4 to 6 weeks but full recovery of energy can take longer. Patience pays off.

Iron infusions

When oral iron does not work, is not tolerated or recovery is too slow, iron can be given by infusion. The procedure is straightforward and replenishes iron stores quickly. NHS access varies by area and is more readily available in some circumstances than others. Private iron infusions are widely available. Speak to your GP about whether iron infusion is appropriate.

More on female health

For heavy periods context our Common Menstrual Irregularities and What Causes Them covers the main cause. Why Magnesium Iron and Zinc Matter for Women covers iron alongside other key minerals. And What to Eat During Pregnancy covers the pregnancy demand.