The vitamins you need during pregnancy – and why

Are you pregnant and totally confused about the pre-pregnancy vitamins you should be taking?

Perhaps you even question the need for pregnancy vitamins, as you feel you should be able to get the nutrients you need through diet alone?

In this article, we give you the facts which vitamins you need during pregnancy, and why.

We will also let you know where these vitamins can be found in foods, and the right amount to take in supplements.

Do I need to take pre-pregnancy vitamins?

The bottom line is – you should, but there’s only a certain few which you may actually need.

When you’re pregnant, your requirement for certain nutrients increases. The need for extra vitamins in pregnancy is partly due to the extra demand placed on your body during this time, as well as the fact that your growing baby relies on you for nutrients with which to build strong bones, teeth, blood and tissues.

With some vitamins, it’s difficult to ensure we’re getting the amounts we need during pregnancy from diet alone.

Therefore, a supplement will give you the best chance of having a healthy pregnancy and offer a safeguard against certain preventable conditions and complications.

Essential vitamins you need during pregnancy and why 

Here are 5 of the most important vitamins to support your health during pregnancy. 

1. Folic acid 

What is it?

Folic acid also goes by the names vitamin B9 and folate.

Folate refers to the natural form of vitamin B9 which is found in food. Folic acid is the man-made kind, which is found in vitamin supplements.¹

Why is it important for pregnancy?

One of the most important vitamins for pregnancy, folic acid is associated with the healthy development of babies, especially during early pregnancy which is when the baby’s growth is most rapid.

Studies have shown that taking folic acid during early pregnancy reduces the risk of the baby developing neural tube defects – which are birth defects of the brain and spinal cord including spina bifida and anencephaly.²

The highest level of protection comes from when a woman takes folic acid in the months leading up to conception, as the levels of folic acid take time to build up in the body.

However, if you didn’t do this, you should always begin taking folic acid as soon as you find out you’re pregnant.

How much should you take?

According to the NHS, you should take 400mcg folic acid supplement every day until you’re 12 weeks pregnant.³

Even a very healthy diet won’t contain the levels of folic acid you need during pregnancy.

If you have severe morning sickness or HG, you might find that taking a bulky pre-natal supplement is out of the question. Don’t skip the folic acid, though. Try a smaller folic acid-only supplement which may be easier to stomach if you’re feeling sick.

What foods contain folic acid?

It’s also widely available in many foods, such as:⁴

• broccoli
• leafy greens e.g. spinach and kale
• fortified cereals
• chickpeas and beans
• pasta

Folic acid is water-soluble, which means it can’t be stored in the body, so you need it every day.

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2. Vitamin D

What is it?

Vitamin D is an essential vitamin which helps regulate the amount of calcium and phosphate in the body, which is vital for healthy bones, teeth and muscles.⁵

Vitamin D is one of the best pregnancy vitamins to take.

Why is it important for pregnancy?

During pregnancy, your body’s requirement for vitamin D increases as it’s needed for the healthy development of your baby’s musculoskeletal system.⁶

In fact, babies whose mothers are deficient in vitamin D are at risk of decreased bone mass and rickets.⁷

Further, running low on vitamin D during pregnancy can be bad news for your health, too. Studies have linked low levels of vitamin D during pregnancy with conditions such as high blood pressure, gestational diabetes, pre-eclampsia, low birthweight and early delivery.⁸

This, together with the fact that approximately 1 in 5 people in the UK have low vitamin D levels, which is why it’s recommended that you take a vitamin D supplement throughout your pregnancy.⁹

How much should you take?

It’s very difficult to get enough vitamin D from diet alone. Most of our vitamin D comes from sunlight, so during the less sunny months it’s recommended that you take a vitamin D supplement.

A 10 microgram supplement of vitamin D is enough to provide adequate levels for both you and your baby. You should take this supplement after pregnancy too, to help support breastfeeding if that’s what you choose, as well as your general health.¹⁰

What foods contain vitamin D?

Vitamin D is found in foods such as:¹¹

• oily fish
• eggs
• fortified foods such as breakfast cereals

Handpicked content: The best sources of vitamin D: Are you getting enough? 

3. Iron

What is it?

An essential mineral, the body needs iron to grow and release energy as fuel.

Iron is also needed to make haemoglobin, which is the protein red blood cells use to carry oxygen around the body.¹¹

Why is it important for pregnancy?

During pregnancy, you produce around an additional 50% of blood volume compared to your usual levels.¹³ This additional blood requires extra iron to make extra haemoglobin, to support the placenta and ensure enough oxygen is getting to your baby.

If you’re low on iron, the amount of haemoglobin in your blood decreases. This can reduce the oxygen supply to cells and organs. During pregnancy, this is particularly relevant as your baby is relying on you to provide their oxygen.¹⁴

Due to the increased need for iron, anaemia is common among pregnant women. Anaemia makes you feel tired and exhausted, and severe anaemia can cause complications during pregnancy.¹⁵

Low iron levels or anaemia will be picked up during your routine blood tests – it’s vital that you access prenatal care and attend every appointment.

Not all pregnant women will have low iron levels but taking an iron supplement will safeguard you against developing anaemia during pregnancy.¹⁶ You might be more at risk of low iron if you don’t eat meat.

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How much should you take?

Pregnant and breastfeeding women need around 20 to 30 mg of iron per day, unless you’ve been diagnosed with anaemia, in which case you will be prescribed a higher dose up to 120mg as advised by your midwife or GP.¹⁷

What foods contain iron?

• meat and fish
• dried fruit
• nuts
• soybean flour
• chickpeas and other beans¹⁸

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4. Calcium

What is it?

An essential mineral, calcium is important for healthy bones and teeth, muscle contractions including the heartbeat, and the normal clotting of blood.¹⁹

Calcium is the most abundant mineral in our bodies, but we can’t produce it on our own and must get it from our diets.

Most of the 1kg of calcium in our bodies is found in our bones.²⁰

Why is it important for pregnancy?

As calcium is vital for growing healthy bones, it’s no surprise that during pregnancy our requirement increases – you’re growing a whole extra skeleton!

You may already know that your baby will take calcium from their mother’s bones if enough isn’t readily available from the mother’s diet. This puts you at risk of decreased bone mass and eventually, osteoporosis.²¹

Most of your baby’s bone growth occurs from mid-pregnancy onward, with maximal calcium requirement occurring during the third trimester.²²

As well as helping your baby grow, calcium supplementation also decreases the risk of developing certain complications during pregnancy These include hypertensive disorders and preeclampsia.²³

How much should you take?

The NHS recommends everyone get 700mg calcium per day.²⁴

In pregnant women whose calcium intake is particularly low, calcium supplementation is recommended by the World Health Organisation.²⁵

Most women in the UK will have normal levels of calcium, however.

Concentrate on getting your 700mg daily from your diet, and take a calcium supplement as a top-up, speaking to your midwife or GP if you have any concerns.

It’s worth noting that pregnant women absorb more calcium from diet and supplements than anyone who isn’t pregnant, making it easier to get your daily amount.²⁶

What foods contain calcium?

Luckily, there are plenty of food sources which are rich in calcium. These include:²⁷

• milk, cheese and yoghurt
• fortified soya milk
• leafy green vegetables, such as kale, okra and spinach
• sardines and pilchards
• bread made with fortified flour

What about if your diet is calcium-free? Check out these 6 sources of vegan calcium! 

5. Omega 3 fatty acids 

What is it?

Docosahexaenoic acid (DHA) is an omega 3 fatty acid.

Omega 3 fatty acids are essential nutrients which we can only get from our diets. They’re important for a healthy brain and cardiovascular system.²⁸

Why is it important for pregnancy?

During pregnancy, you need omega 3 fatty acids – in particular DHA – in order to develop your baby’s brain, central nervous system and eyes.^29,30

Having adequate levels of DHA during pregnancy has been linked with the baby having a slight developmental advantage over babies born to mothers who were low on DHA during pregnancy.³¹

Further, pregnant women with low levels of omega 3 fatty acids are thought to be up to 10 times more likely to give birth prematurely.³²

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How much should you take?

Due to pregnant women having to avoid eating too much seafood due to its potential mercury content, many pregnant women likely do not get enough omega-3 fatty acids in their diet.³³

Therefore, a supplement is a good idea.

Generally, the recommendation for pregnant women is a minimum of 200 mg of DHA daily from either food sources or an omega-3 supplement that contains DHA.^34,35

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What foods contain omega 3 fatty acids?

The best source is fish – but be careful, as it’s recommended that pregnant women don’t exceed 2 servings of fish per week.

Vitamins in pregnancy – FAQs 

There's a lot to learn when it comes to pregnancy nutrition. We've gathered together some of the most frequently asked questions so you can make sure you know everything you need to support you and your baby during pregnancy. 

What does vitamin A do in pregnancy? 

Getting too much vitamin A while you’re pregnant can harm your baby. Excessive vitamin A intake in pregnancy can affect the baby’s central nervous and cardiovascular systems.³⁶

There’s no need to panic – for most people the risk is low as most foods only contain vitamin A in small amounts. However, you should not take any supplements containing vitamin A in pregnancy. Vitamin A is fat soluble, which means it is stored in your body’s fat cells, which means your levels can build up.³⁷

Further, you should avoid foods which are rich in vitamin A, such as liver or pate to avoid getting too much.

How much vitamin A is safe for pregnancy?

Although excessive amounts can be harmful, pregnant women need adequate vitamin A levels for good health.

So, what counts of ‘excessive levels’?

There hasn’t been a definitive research study, as obviously researchers can’t use pregnant women in their studies. However, observational studies have found that when the dose of vitamin A is above 10,000 IU (or 3,000mcg) per day, there may be a potential risk.³⁸

Bear in mind, this refers to preformed vitamin A such as the type you find in supplements. It doesn’t apply to the type of vitamin A found in carrots for instance, which is actually carotene which converts to vitamin A only if the body needs it.

How can I boost my immune system while pregnant? 

Your immune response changes when you’re pregnant, so that your body doesn’t attack the foetus as an invader. As a result, you become more susceptible to some viruses and infections.³⁹

To keep your immune system strong, prioritise eating several different types of fruit and vegetables each day, and drink 8 glasses of water.

A combination prenatal vitamin will help top up your levels of certain vitamins associated with good immunity, such as vitamin C.

Plenty of rest is also key – lack of sleep can throw off the immune system and make it more likely for you to fall ill.⁴⁰

If you have severe morning sickness and can’t keep food or supplements down, talk to your midwife and GP. In some cases, intravenous (IV) infusion of some vitamins is an option to ensure you’re not low.

Summary 

• A healthy diet is essential for a healthy pregnancy
• Some nutrients should be supplemented as you can’t get enough from diet alone 
• You should take a folic acid and vitamin D supplement while you’re pregnant
• Calcium, iron and omega 3 supplements may also ensure you stay healthy and help protect against complications

Last updated: 2 June 2021