folic acid is very important in the formation of the spinal column n nerves of a lo and preventing birth defects in particular spina bifida.
its best to start taking folic acid at least 3 months prior to trying, throughout ttc and into week 13, also its reported to be wise to take throughout pregnancy but those first 13 weeks are most important.
i take santogen pro natal as it contains folic acid and is a multi vitamin have been since ttc throughout my short preg, bk to ttc and now wtt, in short im just not stopping taking them!