Folic acid, also known as vitamin B9, can reduce the risk of your baby developing a neural tube defect, such as spina bifida, by as much as 70 per cent.
When to take folic acid
The Department of Health recommends women who are planning a pregnancy take a 400mcg a day folic acid supplement, before conception, and for the first three months of pregnancy, when your baby's neural tube (which forms the brain and spinal cord) is developing.
It's also safe to carry on taking folic acid throughout your pregnancy.
The advice is that the dosage should be increased to a prescription of 5mg a day if you've had: a previous pregnancy affected by a neural tube defect; you or your partner have a neural tube defect or a family history of neural tube defects; or you have diabetes.
Can you get enough folic acid from your diet?
The dietary form of folic acid is called folate and is found in foods such as yeast extract, wholegrain cereals, liver, Brussels sprouts, leafy green vegetables, asparagus, brown rice beans, oranges and beer. It is also added to some breakfast cereals.
Folate is also found in liver – but it's not safe to eat liver if trying to conceive or during pregnancy because of its high vitamin A content, which can damage a baby's eye development.
Folate is water-soluble and can't be stored in the body for long, so you need to top up your levels regularly. And up to 50 per cent of folate in foods can be destroyed by cooking or keeping the food which contains it in the fridge for too long.
For these reasons, folic acid supplements are recommended for women trying to conceive (for at least one month before conception) and during the first three months of pregnancy.
What is spina bifida?
Spina bifida means 'split spine ' – it's caused when the neural tube from which the spine and central nervous system develops fails to close, leaving a gap.
Scientists don't know what causes this to occur, but they do know that taking folic acid can reduce the risk of it happening.
Other ways to boost your pre-conceptual health
Give up smoking: Smoking may affect your fertility, so if you or your partner are smokers, get help to quit. For information, call the NHS Smokefree helpline on 0300 123 1044.
Avoid alcohol: The Chief Medical Officer recommends women planning to become/ or who are now pregnant, should avoid alcohol to minimise risks to their baby.
Keep to a healthy weight: If you're overweight or underweight it can affect your fertility as your periods may become irregular or stop.
Eat well: Develop healthy eating habits before you conceive, making sure you eat a wide range of food groups, including at least five portions of fruit and vegetables a day, wholegrains, lean protein, oily fish, dairy products, nuts and legumes.
Consider a supplement: Specially-formulated pre-conceptual vitamin supplements are available containing folic acid and zinc, to support conception and fertility for men and women. A 2016 review of studies concluded zinc levels are lower in the semen of infertile males when compared to men with normal fertility – and that a zinc supplement could significantly increase semen volume, sperm motility (how well sperm swim) and the percentage of normal-shaped sperm. The authors concluded zinc supplements may increase male reproductive function, but more studies are needed.