Anaemia and low iron pregnancy: causes, symptoms and treatment

Last modified on Friday 8 January 2021

Iron-deficiency anaemia affects almost one in four mums-to-be. Commonly caused by increased blood supply and low iron levels during your pregnancy, it's easy to detect with a routine blood test. We look into the signs and symptoms of this condition, as well as the best treatment for it.

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What is anaemia?

Anaemia is when your blood doesn't contain enough healthy red blood cells – these are responsible for carrying oxygen around the body and are produced by eating a diet that's rich in iron and other nutrients.

Not getting enough can leave you feeling tired, lacking in energy, or even dizzy.

If you develop anaemia or low iron in pregnancy, this can mean that your baby doesn't get enough oxygen. It can also lead to other pregnancy and labour complications, if left untreated.


Types of anaemia in pregnancy

There are three main types of anaemia that can develop during pregnancy:

  • iron-deficiency anaemia
  • folate-deficiency anaemia
  • vitamin B12 deficiency.

Although a lack of folate (vitamin B9) or vitamin B12 can cause anaemia, iron-deficiency anaemia is the most common type of anaemia in pregnancy.

What causes anaemia in pregnancy?

When you're pregnant, your body produces lots more blood, to deliver nutrients to your growing baby. As you produce more blood, you need more iron, and it can be difficult to get enough through food alone.

In order to produce enough red blood cells for your pregnancy, you may need an iron supplement to be prescribed, as well as upping your iron intake through a healthy diet.

See below for more about treating anaemia.

What are the signs and symptoms of anaemia?

Although your blood will be screened for anaemia during pregnancy (see above) you may also notice some of the following symptoms affecting your health and wellbeing.

According to the NHS , the main symptoms of iron deficiency anaemia are:

  • tiredness
  • lack of energy
  • breathlessness (feeling short of breath)
  • heart palpitations (noticeable heartbeats)
  • pale skin

According to , you may also feel more dizzy than usual, though dizziness can be a common pregnancy side-effect anyway due to a decrease in blood pressure.

What's the test for anaemia in pregnancy?

It's thought that almost one in four pregnant women in the UK have iron-deficiency anaemia or experience low iron in pregnancy. This increases to one in three after the birth.

As it's fairly common, you'll be automatically screened for it at your booking appointment as well as in your 28-week antenatal appointment.

This is done by a simple blood test that checks the haemoglobin levels (the red blood cell count) in your blood, which will give a diagnosis as to whether you are indeed anaemic.

If you notice the symptoms of anaemia below though, you don't have to wait until your next routine test; speak to your midwife or GP.

How much iron do I need in pregnancy?

The World Health Organisation (WHO) defines anaemia as 'a haemoglobin concentration of less than 110g per litre of blood'.

This differs slightly depending on what stage of your pregnancy you're at.

In your first trimester, your iron levels (haemoglobin levels) should be around 110g/l at your booking appointment. In your second and third trimester, your iron levels should be above 105g/l.

OK, but what does that mean?

Of course, there's no way of telling how much iron you have in your blood without a blood test! What you can control though, is how much iron you eat during pregnancy.

According to the NHS, women who aren't pregnant need to get 14.8mg of iron a day from their food. The amount of iron you need gradually increases throughout your pregnancy; by the start of the third trimester, you should aim for about 30mg.

It can be hard to get all the iron you need in late pregnancy, but we've listed some iron-rich foods below that will help.

There are loads of food calculators online that can help you work out exactly how much iron you're getting. But try not to worry too much, just aim to include as many iron-rich foods in your diet as you can.

Should I take an iron supplement just in case?

It's currently not recommended that pregnant women take an iron supplement 'just in case'.

NICE recommends women should take a 400 microgram dose of folic acid each day, from before pregnancy until the end of the first trimester (first 12 weeks), and 10 micrograms of vitamin D daily throughout pregnancy and while breastfeeding. No other supplements are recommended for routine use.

This is partly due to side-effects that iron supplementation can cause, such as stomach irritation and constipation or diarrhoea.

It's also because pregnant women with low haemoglobin levels can then be investigated and treated once anaemia is diagnosed.

Don't take over-the-counter iron tablets during pregnancy. If you need extra iron, your GP can prescribe you a supplement with a much higher dose.

Am I likely to become anaemic during pregnancy?

Although anyone can get anaemia in pregnancy, there are some factors that will increase your chances of being anaemic or suffering from a low iron pregnancy.

These include:

  • being anaemic already (pre-pregnancy)
  • having a blood condition already (sickle cell or thalassaemia)
  • having an inflammatory disorder that affects the gut being able to absorb iron from food (coeliac, inflammatory bowel disease)
  • expecting twins or triplets
  • if you gave birth less than a year ago
  • being pregnant when you're under the age of 20

What are the best iron-rich foods to eat?

With increased blood volume during pregnancy, it's a good idea to try and maintain (or improve) your haemoglobin levels by increasing your iron intake through a healthy diet. So take care to ensure you are eating balanced, nutritional foods, high in iron.

Foods that include iron are:

  • red meat – but avoid eating liver as it is high in retinol (the animal form of vitamin A), which may harm your unborn baby
  • pulses and beans (such as red kidney beans, edamame beans and chickpeas)
  • dried fruit (such as dried apricots)
  • nuts
  • soy bean flour
  • breakfast cereals that have been fortified in iron

Some food and drink can affect how the body absorbs the iron from the meals you're eating:

Vitamin C

Not only is vitamin C good for you, it also helps the body to absorb iron. Try drinking fresh orange juice with meals, or having vitamin-C rich foods alongside iron-rich foods.

Good sources of vitamin C include: citrus fruit (including oranges), bell peppers, strawberries, blackcurrants, broccoli, brussels sprouts and even potatoes.

Tea and coffee

These have the opposite effect to vitamin C, and make it harder for your body to absorb iron from the food you eat.

You probably already know that you should limit the caffeine you have in pregnancy to no more than 200mg a day (about two cups of coffee, or three cups of tea).

However, even decaff versions can affect your iron absorption (it's the polyphenols in tea and coffee that affect iron absorption, not the caffeine). So it's best to cut down on these during pregnancy, too.

Although increasing your iron intake will help, it may not necessarily reverse your anaemia.

This could be because your gut is unable to absorb the iron from your diet, or your baby's iron requirement is so high that it's just not possible to get this from diet alone.

If you are suffering from anaemia during pregnancy, you'll most likely be prescribed an iron supplement to help restore your levels as quickly as possible.

What's the difference between haem iron and non-haem iron?

Haem iron is the name for iron that comes from meat, poultry and fish. Non-haem iron comes from plant sources, such as beans, pulses and nuts.

Haem iron is more easily absorbed by the body. If you're vegetarian or vegan , it can be even more difficult to get all the iron you need from food, though it's not impossible.

If you're having mostly non-haem iron during pregnancy, it's even more important to have foods or drinks containing vitamin C alongside your iron-rich foods, and to avoid tea and coffee – this will all help your body absorb more of the iron.

Making sure your body has all the nutrients it needs during pregnancy is so important. Pregnacare tablets contain 19 different vitamins and minerals and can be taken all through pregnancy. See more details here at Amazon.

What's the treatment for anaemia?

If you're less than 34 weeks pregnant and anaemic, your GP or midwife will recommend you take an iron supplement. According to , this will usually be 100-200mg of iron per day, depending on how much your GP thinks you need.

You'll usually need to keep taking the iron tablets for three months, and at least six weeks after you have your baby. You may be offered extra blood tests to check that the supplements are working.

If you have extremely low iron levels, severe symptoms, or are more than 34 weeks pregnant when you become anaemic you may need to have iron fed directly into your bloodstream.

This is because there may not be enough time for iron tablets to restore your levels before the baby comes. In this instance, you'll have intravenous (IV) iron.

IV iron is given at the hospital where you'll be closely monitored during and for about half an hour after having it although side effects and complications are rare.

How to take iron tablets

When it comes to supplementation, how well iron tablets work depends on how you take them. Taking them with vitamin C will help the gut absorb the iron.

The NHS recommends taking your iron tablets with a glass of orange juice (or any drink containing vitamin C). It also advises taking them with or soon after food, in order to minimise side-effects. advises that you don't have tea, coffee, or calcium-rich foods (such as milk, cheese or yoghurt) at the same time as taking your iron tablets, as these can all reduce the amount of iron absorbed by the body.

Remember to always keep iron supplement tablets out of the reach of children. An overdose of iron in a young child can be fatal.

What are the side-effects of iron tablets?

Unfortunately, iron tablets can have some unpleasant side-effects, including:

  • constipation or diarrhoea
  • tummy pain
  • heartburn
  • feeling sick
  • black poo

Some of these, such as heartburn and sickness , can be common pregnancy complaints in their own right. Taking your iron tablets with or soon after food may help to reduce the other side-effects.

But if you're really struggling with the side-effects, ask your GP to switch you on to a different type.

Will anaemia harm my unborn baby?

If your iron stores are low, this could affect your overall health as well as your pregnancy and delivery.

Left untreated, anaemia can cause you to:

  • go into labour early
  • have a smaller baby because your placenta may not work as efficiently, decreasing fetal weight
  • bleed heavily when your baby is delivered
  • be at increased risk of infection

Will anaemia affect my birth?

Yes, anaemia can also affect your birth as well as you and your baby's health.

If you're anaemic, you'll be at higher risk of needing a blood transfusion either during or after you've given birth.

Anaemia can also cause extreme tiredness and affect milk production once you've had the baby.

It can also contribute to postnatal depression (PND), so it's also important to report any symptoms of anaemia to your GP after the birth.

Fortunately, getting the right treatment can reduce all these risks, so do talk to your GP or midwife if you have any concerns about your iron levels.

For more information on low iron pregnancy, anaemia, and how a nutritional diet can help, read on below, and chat to other mums-to-be in our forum:

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