Mums, is it best to take folic acid only once you're pregnant, or even while you're trying to conceive?

Yes. You can start to take folic acid when you are preparing to conceive. Folic acid is essential in developing bundle of nerves also known as neural tube which are use in building baby's spine & nervous system. Neural tube is form in early pregnancy when you may not realise you've conceived. Hence you should start taking folic acid as soon as you are trying for a baby. http://www.babycentre.co.uk/x2232/how-much-folic-acid-do-i-need-to-take-while-trying