Folic acid in pregnancy: what you need to know
It's an important little tablet in pregnancy, so when should you start taking folic acid, what does it do, and what happens if you forget to take it (it's fine, lots of us have done it)...
Folic acid is an important supplement for the early months of your pregnancy.
Folic acid is actually the manufactured (synthetic) form of Vitamin B9, aka folate, and the NHS recommends that you take 400mcg every day from before you are pregnant to the end of your 12th week of pregnancy.
IMPORTANT UPDATE (Sep 2021): The UK government has announced plans to fortify non-wholemeal wheat flour with folic acid. This does not change the NHS official advice to take a folic-acid supplement daily for the 12 weeks of pregnancy and while trying to conceive.
In this article, we'll explain:
- When and how should I take folic acid supplements?
- What if I haven't been taking folic acid?
- Where do I get folic acid supplements?
- Can you take too much folic acid?
And answer any other questions you might have about your daily dose of folic acid, and how it affects your unborn baby...
Folic acid is very important to the healthy development of a foetus and much of this key physical development occurs in the earliest weeks of pregnancy.
Folic acid is needed to help the early growth and development of the placenta and helps in the production of the extra blood cells women need when they're pregnant.
Most importantly it can reduce the risk of defects to the brain and spinal cord known as neural tube defects (NTDs), such as spina bifida. NTDs affect up to 1,200 pregnancies a year in the UK according to the Association for Spina Bifida and Hydrocephalus (ASBAH).
There's another reason too why you should increase your intake of folic acid when you're in baby-making mode: it's usual that folic acid is removed from the blood quite quickly, but when you're pregnant it disappears even faster. Yep, the kidneys filter it out of your blood at four times the normal rate when you're expecting.
So if you don't eat folic acid-rich foods or take folic acid supplements regularly, you can become relatively deficient in folic acid and your levels may drop low enough to put your baby at risk.
“During the third week of an embryo’s life, a thickening forms along the length of its back where the spine will eventually develop,” explains Dr Sarah Brewer.
“The edges of this thickening grow upwards, forming a central groove. This neural groove continues to deepen and its walls fold over until they meet.
"After 3 or 4 days, fusion completes to form the neural tube. The tube develops into the spinal cord.
"If the tube fails to close properly, part of the spinal cord is left exposed to cause spina bifida. Taking folic acid reduces the risk of that happening."
If you have unexpectedly become pregnant, it's advised you start taking folic acid straight away if you're less than 12 weeks pregnant.
And remember, it's rare for babies to be born with neural tube defects, so if you haven’t taken folic acid in the first few or even 12 weeks, it doesn’t mean your baby will automatically have problems.
“But if you’ve found out you’re pregnant then start taking folic acid straight away,” says Dr Philippa Kaye. “It’s difficult not to worry - but remember your foetus will always be closely monitored.”
What if I'm trying to get pregnant?
if you are considering getting pregnant, you should start taking 400mcg per day of the supplement ideally 3 months before you try to conceive.
Folic acid can be found in:
- Dark green vegetables such as spinach and broccoli
- Some cereals
But, because it's not stored in the body and needs to be incorporated into your diet daily, to be absolutely sure you're getting at least the recommended amount of folic acid every day it's best to take a supplement - as well as eating food rich in it.
Dietitian Caroline tells MFM: "Eating a healthy diet when you're pregnant will ensure you get enough of most vitamins and minerals, but there are some important exceptions, including folic acid, which is one of the B group vitamins.
"You should also aim to eat plenty of food rich in folic acid. It occurs naturally but is also added to some manufactured foods.
"Good sources include green vegetables such as spinach, broccoli and green beans; bread, particularly wholemeal or fortified bread; fortified breakfast cereals; bananas and citrus food including oranges and grapefruit; beans and pulses such as chickpeas or baked beans; milk and yoghurt; and yeast extract such as Marmite."
But isn't folic acid being added to flour in the UK?
In September 2021, the UK government announced that folic acid is to be added to non-wholemeal wheat flour (but not gluten-free foods and wholemeal flour). This already happens in several countries around the world, and is considered perfectly safe.
All it means is that all non-wholemeal flour and flour-based products (like bread) will be fortified with folic acid (as many breakfast cereals already are), and this would provide most people in the UK with the recommended amount.
It's thought this would provide a 'safety net' for pregnant women who may not have know they are pregnant before 12 weeks, or aren't aware they should take a folic acid supplement.
Importantly, this move to fortify flour doesn't mean you don't need to take folic acid supplements anymore if you're pregnant or trying to conceive. The official NHS advice – to take a 400mcg folic acid tablet every day before pregnancy and until you are 12 weeks pregnant – still stands.
You'll find folic acid supplements in chemists and health food shops, either as just folic acid or combined with other supplements for pregnancy.
If you're a cereal eater then you can also look out for cereal fortified with 100% of the daily recommended intake of folic acid. (But make sure you then eat the right portion of cereal!)
"Taking a daily 400mcg folic acid supplement from before you start trying to get pregnant until the end of the first trimester (about 13 weeks into pregnancy) can cut your baby’s risk of spina bifida by up to 75%," says Dr Sarah Jarvis GP.
More like this
And it's good to note that supplements are better absorbed if you don't take it on an empty stomach.
Speaking about taking it, and how she found it, one of our mums, Greta, said: "I started taking folic acid about six months before I ended up getting pregnant, so by the time I was expecting, I got a bit lazy about remembering to take it.
"I did keep it up and just avoided fretting about it on the days I forgot. One of the great things is that, unlike some supplements, folic acid doesn’t seem to make you feel queasy, which really helps in the first weeks!"
Current NHS guidelines advise that adults take 1.5 mcg a day of vitamin B12, and research from 2012 has advised that taking B12 is important in increasing the effectiveness of folic acid.
Professor John Scott from Trinity College Dublin says: “It is clear that, as well as the addition of a folic acid supplement (400 ug/d), the addition of a vitamin B12 component of at least 2.5 ug/d would bring about a further significant and worthwhile risk reduction for NTDs.”
Dr Rob Hicks, practising GP and sexual health expert, says, “Women should take folic acid and vitamin B12 supplements ideally from 3 months before trying to conceive, while trying to conceive, and then for the first 12 weeks of their pregnancy. The benefits of combining vitamin B12 and folic acid to reduce NTDs are over and above folic acid alone.
“It’s such a simple message, it seems too easy to be true. But it’s a message that doesn’t need to be over complicated,” Dr Hicks adds.
The NHS says that taking 1mg or less of folic acid supplements a day is unlikely to be harmful.
The main reason taking more can be harmful is that it could cover up the symptoms of vitamin B12 deficiency which can eventually damage the nervous system if not spotted and treated - but this is more of a concern among older people.
There was a Canadian study carried out in 2011 on mice which showed that taking too much folic acid during pregnancy led to embryonic delay and growth retardation in mice: this led to concern that an excess of folic acid may have a similar effect in pregnant women too.
However, it's important to note that mice in the research were given 8mg a day of folic acid - that's 20 times the recommended amount - and guidelines for pregnant women and taking folic acid did not change after these results were published.
A 2013 study did suggest that mothers who take folic acid before conceiving and during early pregnancy could cut their child’s autism risk by 40%.
The research, published in the Journal of the American Medical Association, tested 85,000 children and found that those whose mothers who took supplements of folic acid had a significantly lower risk of Autism Spectrum Disorder (ASD).
Scientists from the Norwegian Institute of Public Health and Columbia University recorded information about the participating mothers’ diets, then over the next decade, the children were monitored for ASD.
Researchers concluded that mothers who took the supplement from 4 weeks before conception to week 8 of their first trimester were 40% less likely to have children with the condition.
Pål Surén, a spokesperson for the study has commented: "We examined the rate of autism spectrum disorders in children born to mothers who did or did not take folic acid during pregnancy.
“There was a dramatic reduction in the risk of autistic disorder in children born to mothers who took folic acid supplements.”
A 2009 study carried out by the University of Texas does suggest that thousands of early births could actually be prevented if more pregnant women took folic acid.
Scientists found that women who received folic acid supplementation for a year in the run up to becoming pregnant were 70% less likely to give birth prematurely.
Those who took folic acid for a year before pregnancy were also 50% less likely to have a child at between 28 and 32 weeks, it was revealed.
For those mums to be who took folic acid for less than a year before conception, there was a far less significant drop in the number of premature births.
A 2009 study found a 30% increased risk of asthma for children whose mums took supplements of the vitamin between weeks 30 and 34 of their pregnancy.
Women trying to conceive are advised to take a supplement of folic acid every day for 3 months beforehand, after stopping contraception, and for the first 12 weeks of pregnancy.
Experts at the University of Adelaide studied 557 expectant mums and looked into how many of their children had asthma at 3-and-a-half years and 5-and-a-half years.
The findings showed a link with folic acid taken beyond 12 weeks, but no association with it taken in early pregnancy.
But British experts are sceptical of the research. Terence Stephenson, from the Royal College of Paediatrics and Child Health, said, “The increased risk, if there is any, is only statistically significant.”
Leanne Metcalf, of Asthma UK, said: "While asthma is a serious and long term condition, the benefits of taking folic acid supplements in pregnancy, particularly with regards to prevention of birth defects like spina bifida, still outweigh the risk of developing asthma."
Possibly. A 2011 study from Norway showed that mums-to-be who take folic acid during the first 2 months of pregnancy are less likely to have children with language learning delays.
The study of 40,000 pregnant women showed a relation between taking folic acid during pregnancy and the amount of words their children could say by the age of 3.
Last updated January 2019
Tara is mum to 1 daughter, Bodhi Rae, and has worked as Content Editor and Social Media Producer at MadeForMums since 2015
Six big family moments that matter – and the products that make them easier to navigate
These products from John Lewis & Partners help support the memorable moments of family life.