Folates are pterin derivatives oxidised to various degrees, which exhibit the biological activity of folic acid. Physiologically, they act as coenzymes (cofactors) essential for ensuring normal metabolism, tissue renewal, and growth, particularly whenever any increasing demands arise due to accelerating cell division and metabolism. The importance of their role in organogenesis is widely recognised during pregnancy. The most common cause of folate deficiencies occurs when there are increased physiological demands for this compound, for instance: during pregnancy (especially in cases of having twins), gastrointestinal (GI) malabsorption of folate, congenital disorders of the GI tract, or if cytostatic medication has been given. Taking folate as a prophylactic measure also reduces rates of megaloblastic anaemia and neural tube defects.