Folic acid is an important component of a mothers' vitamin supplements. It is given pre-conceptually as well as continued to be given through-out first two trimesters of pregnancy. It has been found that folic acid supplementation could reduce developmental defects like neural tube defects. Thus it is important that mothers take these supplementation even prior to conceiving.
Folic acid is used by body's metabolic processors in the synthesis of DNA. Thus it is an important substrate for dividing cells. Folic acid is converted to dihydrofolate and then to tetrahydrofolate, where it is used in the sysnthesis of DNA molecules.