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Iron deficiency anaemia is a condition where a lack of iron in the body leads to a reduction in the number of red blood cells.
Iron is used to produce red blood cells, which help store and carry oxygen in the blood. If you have fewer red blood cells than is normal, your organs and tissues won't get as much oxygen as they usually would.
There are several different types of anaemia, and each one has a different cause. Iron deficiency anaemia is the most common type.
Other types of anaemia can be caused by a lack of vitamin B12 or folate in the body – read more about vitamin B12 and folate deficiency anaemia.
Many people with iron deficiency anaemia only have a few symptoms. The severity of the symptoms largely depends on how quickly anaemia develops.
You may notice symptoms immediately, or they may develop gradually if your anaemia is caused by a long-term problem, such as a stomach ulcer.
The most common symptoms include:
Less common symptoms include:
See your doctor if you experience symptoms of iron deficiency anaemia. They should be able to diagnose the condition using a simple blood test .
Read more about diagnosing iron deficiency anaemia.
There are many things that can lead to a lack of iron in the body. In men and post-menopausal women, the most common cause is bleeding in the stomach and intestines.
This can be caused by a stomach ulcer, stomach cancer, bowel cancer, or by taking non-steroidal anti-inflammatory drugs (NSAIDs) .
In women of reproductive age, heavy periods and pregnancy are the most common causes of iron deficiency anaemia as your body needs extra iron for your baby during pregnancy.
Unless you're pregnant, it's rare for iron deficiency anaemia to be caused just by a lack of iron in your diet. However, if you do lack dietary iron, it may mean you're more likely to develop anaemia than if you have one of the problems mentioned above.
Read more about the causes of iron deficiency anaemia.
Treatment for iron deficiency anaemia involves taking iron supplements to boost the low levels of iron in your body. This is usually effective, and the condition rarely causes long-term problems.
You'll need to be monitored every few months to check the treatment is working and your iron levels have returned to normal.
The underlying cause will need to be treated so you don't get anaemia again. Increasing the amount of iron in your diet may also be recommended.
Good sources of iron include:
Read more about treating iron deficiency anaemia.
If iron deficiency anaemia is left untreated, it can make you more susceptible to illness and infection, as a lack of iron affects the body's natural defence system (the immune system).
Severe iron deficiency anaemia may increase your risk of developing complications that affect the heart or lungs, such as an abnormally fast heartbeat (tachycardia) or heart failure, where your heart is unable to pump enough blood around your body at the right pressure.
Pregnant women with severe or untreated anaemia also have a higher risk of complications before and after birth.
Read more about the complications of iron deficiency anaemia.
Many people with iron deficiency anaemia will only display a few signs or symptoms of the illness.
The most common symptoms include:
Less common symptoms include:
You may also notice changes in your physical appearance. For example, signs you may have iron deficiency anaemia include:
The severity of your symptoms can depend on how quickly your anaemia develops. For example, you may notice few symptoms or they may develop gradually if your anaemia is caused by a chronic (long-term) slow loss of blood, such as a stomach ulcer.
Iron deficiency anaemia occurs when the body does not have enough iron. A lack of iron can be caused by a number of factors.
Some are outlined below.
In women of reproductive age, periods are the most common cause of iron deficiency anaemia.
Usually, only women with particularly heavy periods develop iron deficiency anaemia. If you have heavy bleeding over several consecutive menstrual cycles, it is known as menorrhagia.
It is very common for women to develop iron deficiency during pregnancy. This is because your body needs extra iron so your baby has a sufficient blood supply and receives necessary oxygen and nutrients. Many pregnant women require an iron supplement, particularly from the 20th week of pregnancy.
Your gastrointestinal tract is the part of your body responsible for digesting food. It is made up of the:
Bleeding in the stomach and intestines is the most common cause of iron deficiency anaemia in men and in women who have been through the menopause (when a woman’s monthly periods stop).
Some of the causes of gastrointestinal bleeding are outlined below.
If your doctor suspects your medication is causing gastrointestinal bleeding, they may be able to prescribe a less harmful medicine as an alternative. Do not stop taking a medicine prescribed for you unless your doctor advises you to.
The acid in your stomach (which usually helps your body to digest food) can sometimes eat into your stomach lining. When this happens, the acid forms an ulcer (an open sore). This is also known as a peptic ulcer.
Stomach ulcers can cause your stomach lining to bleed and this blood loss can lead to anaemia. In some cases the blood loss can cause you to vomit blood or pass blood in your stools (faeces). However, if the ulcer is slow bleeding, you may not have any symptoms.
In some rare cases, gastrointestinal bleeding can be caused by cancer, usually of the stomach or colon (part of the bowel, which makes up the digestive system).
In diagnosing the cause of your anaemia, your doctor will check for possible signs of cancer. If your doctor suspects cancer, you will be immediately referred to a gastroenterologist (a specialist in treating conditions of the digestive system) for a more thorough examination. This way, if cancer is found, it can be treated as quickly as possible.
Gastrointestinal bleeding can also be caused by a condition called angiodysplasia. This is an abnormality of blood vessels in the gastrointestinal tract that can cause bleeding.
Many people with chronic kidney disease (CKD) develop iron deficiency anaemia.
Most people with kidney disease will be given iron supplements through an injection administered intravenously (into a vein). However, daily ferrous sulphate tablets may be tried first.
Other conditions or situations that cause blood loss and may lead to iron deficiency anaemia include:
Malabsorption (when your body cannot absorb iron from food) is another possible cause of iron deficiency anaemia. This may occur if you have:
Unless you are pregnant, it is rare for iron deficiency anaemia to be caused solely by a lack of iron in your diet.
Some studies suggest vegetarians or vegans are more at risk of iron-deficiency anaemia due to the lack of meat in their diet. However, it is possible to gain enough iron in a vegetarian or vegan diet through other types of food such as:
Pregnant women may have to increase the amount of iron-rich food they consume during their pregnancy to help avoid iron deficiency anaemia.
Read more information about good sources of iron.
See your doctor if you experience symptoms of iron deficiency anaemia. A blood test will be able to confirm the diagnosis.
Your doctor may also ask questions and carry out a physical examination to find the cause of your anaemia.
To diagnose iron deficiency anaemia, a blood sample is taken from a vein in your arm and a full blood count is made. This means all the different types of blood cells in the sample will be measured.
If you have anaemia:
Your doctor may also test for a substance called ferritin, a protein that stores iron. If your ferritin levels are low, you do not have much iron stored in your body and may have iron deficiency anaemia.
Read more information about blood tests.
If your doctor suspects your anaemia may be due to a vitamin B12 and folate deficiency, rather than an iron deficiency, your levels of these substances may be tested. Folate works with vitamin B12 to help your body produce red blood cells.
Vitamin B12 and folate deficiency anaemia is more common in people who are over 75 years of age.
To determine the underlying cause of your anaemia, your doctor may ask questions about your lifestyle and medical history. For example, you may be asked about:
A physical examination will usually only be necessary if the cause for your iron deficiency anaemia has not been found.
Your doctor may:
Two other possible types of physical examination you may have are explained below.
A rectal examination is generally only necessary if there is rectal bleeding. This is a common procedure which can help your doctor determine whether there is something in your gastrointestinal tract that may be causing bleeding. Your doctor will insert a gloved, lubricated finger into your rectum so they can feel for abnormalities.
A rectal examination is not something to be embarrassed about as it is a procedure your doctor will be used to performing. It should not cause significant pain or discomfort and you will only usually feel a slight sensation that your bowels are moving around.
Women may have a pelvic examination if their doctor suspects heavy menstrual bleeding (menorrhagia) may be the cause of their anaemia.
During a pelvic examination, your doctor will examine your vulva and labia (external sex organs) for signs of bleeding or infection. They may also examine you internally. This will involve your doctor inserting gloved, lubricated fingers into your vagina to feel whether your ovaries and uterus (womb) are tender or enlarged.
A pelvic examination will not be carried out without your consent, and you will have the option of having someone with you during the procedure.
Iron deficiency anaemia is common during [pregnancy] so your doctor will only look for an alternative cause if your haemoglobin level is particularly low, or if your symptoms or medical history suggest your anaemia may be caused by something else.
Your doctor may refer you to a gastroenterologist (a specialist in treating conditions of the digestive system), who will be able to carry out a more thorough examination, if:
If you are a woman with heavy periods (menorrhagia), you may be referred to a gynaecologist if you fail to respond to treatment with iron supplements.
Treatment for iron deficiency anaemia usually involves taking iron supplements to replace missing iron and making necessary changes to address the underlying cause.
Your doctor will prescribe an iron supplement to restore iron missing from your body. The most commonly prescribed supplement is ferrous sulphate, taken orally (by mouth) two or three times a day.
Some people can experience side effects when taking iron supplements including:
These side effects should settle down over time. Taking ferrous sulphate with food or shortly after eating may help minimise side effects. Your doctor may also recommend you only take one or two tablets a day, instead of three, if you are finding side effects difficult to cope with.
If ferrous sulphate is not suitable because of side effects, you may be prescribed a different iron supplement called ferrous gluconate. This supplement should cause fewer side effects because it contains a less concentrated dose of iron. However, it may take longer for iron levels in your body to be restored.
If you have young children, it is important to store iron supplements out of their reach. This is because an overdose of iron supplements in a young child can be fatal.
If a lack of iron in your diet is thought to contribute to your iron deficiency anaemia, your doctor will advise on how to include more iron in your diet.
Iron-rich foods include:
To ensure a healthy, well-balanced diet, include foods from all major food groups in your diet. If you have iron deficiency anaemia, eat plenty of iron-rich foods, such as those listed above.
However, some foods and medicines can make it harder for your body to absorb iron. These may include:
If you are finding it difficult to include iron in your diet, you may be referred to a dietitian (a health professional who specialises in nutrition). They can give you detailed, personalised guidance about how you can change your diet.
Your doctor will also need to ensure the underlying cause of your anaemia is treated so anaemia does not become a recurrent problem.
For example, if non-steroidal anti-inflammatory drugs (NSAIDs) are causing bleeding in your stomach, your doctor may prescribe an alternative type of medicine to help minimise the risk of stomach bleeding.
Heavy periods (menorrhagia) can also be treated in a number of different ways, using both medicines and special internal devices.
Your doctor will ask you to return for a check-up two to four weeks after you have started taking iron supplements to assess how well you have responded to the treatment. Your haemoglobin levels will be checked in a blood test.
If the result of the blood test shows an improvement, you will be asked to return in two to four months for a further blood test.
Once your haemoglobin levels and red blood cells are normal, your doctor will usually recommend you continue taking iron supplements for three months to help replenish the iron stores in your body.
After this, depending on the cause of your iron deficiency anaemia, you should be able to stop taking the supplements. Your condition will then be monitored every three months for one year.
In some people, after iron stores in the body have been replenished, they start to fall again. This could happen if:
In these circumstances, you may be prescribed an ongoing iron supplement. This will usually be one tablet a day. This will stop your anaemia returning.
If your iron levels do not improve, your doctor will ask how regularly you have been taking your iron supplements. Some people are put off taking the medication because of the side effects. However, your conditions will not improve if you do not take the supplements.
If you have been taking the supplements as prescribed and your iron levels have still not improved, your doctor may refer you for an assessment with a specialist.
Iron deficiency anaemia rarely causes serious or long-term complications. However, some people with iron deficiency anaemia find that it affects their daily life.
Some common complications are outlined below.
As iron deficiency anaemia can leave you tired and lethargic (lacking in energy), you may be less productive and active at work. Your ability to stay awake and focus can be reduced, and you may not feel able to exercise regularly.
Research has shown iron deficiency anaemia can affect your immune system (the body’s natural defence system), making you more susceptible to illness and infection.
Adults with severe anaemia may be at risk of developing complications that affect their heart or lungs. For example, you may develop:
Pregnant women with severe anaemia have an increased risk of developing complications, particularly during and after the birth. They may also develop postnatal depression (a type of depression some women experience after having a baby).
Research suggests babies born to mothers who have anaemia are more likely to:
Some cases of restless legs syndrome (RLS) are thought to be caused by iron deficiency anaemia. Doctors may refer to this as secondary RLS.
Restless legs syndrome (RLS) is a common condition affecting the nervous system, which causes an overwhelming, irresistible urge to move the legs. It also causes an unpleasant feeling in the feet, calves and thighs.
RLS caused by iron-deficiency anaemia is usually treated with iron supplements.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.