Iron Deficiency Is Wildly Common In Women. Here's How To Spot It.

Iron deficiency is the most common nutritional deficiency in the world and it is disproportionately a women's condition, for reasons that are not mysterious. It is also routinely missed, because the test most often ordered is the one that goes abnormal last.

Here is what to look for, what to ask for, and why the reference range on your result may not mean what it appears to.

Deficiency comes long before anaemia

Iron stores deplete in stages. First ferritin falls as the body draws down its reserves; only later does haemoglobin drop and the picture become anaemia.

This matters because a full blood count can look entirely normal while stores are nearly empty — and symptoms track stores more closely than they track haemoglobin.

The symptoms that get attributed to something else

Fatigue that sleep does not fix. Breathlessness climbing a flight of stairs you used to manage. Hair shedding. Brittle nails. Restless legs at night. Cold hands. Reduced exercise tolerance that arrives before any drop in training.

And pica — craving and chewing ice in particular — which is unusual enough to be worth mentioning unprompted.

Which test to ask for

Ferritin, alongside a full blood count. Ferritin is an acute-phase reactant, so it rises with inflammation and infection; if there is any question, a CRP measured at the same time makes the ferritin interpretable.

“Laboratory lower limits vary enormously, and some are set at a level where symptomatic women are told they're fine,” says Dr Rahimi. “Many of us treat below 30 micrograms per litre in a symptomatic patient, and a good number of specialists use a higher threshold again in athletes.”

Find the cause, not just the number

In premenopausal women, heavy menstrual bleeding is the most common driver, followed by inadequate intake and malabsorption — coeliac disease in particular.

“The question that changes management is how heavy the periods are, and it is asked far too rarely,” says Dr Boateng. “Flooding, clots larger than a ten-pence piece, changing protection hourly — those are not normal and they are treatable.”

In postmenopausal women, iron deficiency requires gastrointestinal investigation as a matter of course.

Replacing it properly

Oral iron is first line. Current evidence favours alternate-day dosing over daily, because a daily dose raises hepcidin and blunts absorption of the next one.

Take it with vitamin C, away from tea, coffee, calcium and antacids. Expect symptoms to improve over weeks and stores to take three to six months to refill. Do not self-prescribe long term without knowing your ferritin — iron overload is its own problem.