Folate is most important in the very early days of pg when the spine begins to form - so before you even know you are pg and the following weeks. This is why it's so important if you are TTC (or really for anyone of child bearing age who is DTD jic). After that it is still good to take after that - 85% of females in Australia eat less than the recommended allowance of folate - but it's not as important as the early days. It can be taken right through breastfeeding as well, and in fact, even when not pg or bfing.