Folic AcidFolic Acid DeficiencyNeural Tube DefectsTetrahydrofolatesHomocysteineDietary SupplementsFood, FortifiedVitamin B 12Vitamin B ComplexFolic Acid AntagonistsPreconception CareFolate Receptors, GPI-AnchoredHyperhomocysteinemiaAnemia, MacrocyticHematinicsVitamin B 6Pteroylpolyglutamic AcidsVitamin B 12 DeficiencyFolic Acid TransportersPregnancyBreadVitaminsPrenatal CareDouble-Blind MethodFlourFolate Receptor 1