Neural Tube DefectsSpinal DysraphismFolic AcidSpina Bifida OccultaSpina Bifida CysticaAnencephalyNeural TubeMeningomyeloceleFolic Acid DeficiencyEncephalocelePregnancyVitamin B ComplexPreconception CareNeurulationFood, FortifiedDietary SupplementsPrenatal DiagnosisCongenital AbnormalitiesHydrocephalusHomocysteineVitamin B 12Abortion, TherapeuticFourth VentricleInfant, NewbornPrenatal CareTetrahydrofolatesalpha-FetoproteinsMethylenetetrahydrofolate Reductase (NADPH2)Fetal DeathNervous SystemFlourVitamin B 12 DeficiencyAmniotic FluidMethylenetetrahydrofolate Dehydrogenase (NADP)Neural CrestFolate Receptors, GPI-AnchoredIrelandVitaminsEmbryo, MammalianAir Pollution, RadioactiveMouth AbnormalitiesAmniocentesisGene Expression Regulation, DevelopmentalCerebrospinal Fluid ShuntsFolic Acid AntagonistsFetal DiseasesPaired Box Transcription FactorsGestational AgeMeningoceleIndividuationMice, Mutant StrainsCase-Control StudiesPregnancy Trimester, FirstEmbryonic and Fetal DevelopmentPregnancy ComplicationsBreadCentral Nervous SystemFolate Receptor 1Chick EmbryoPrenatal Nutritional Physiological PhenomenaHyperhomocysteinemiaUltrasonography, PrenatalTailAbnormalities, MultipleZinebAbnormalities, Drug-InducedHematinicsMaternal ExposureAbortion, InducedPrevalenceBody PatterningCalifornia5,10-Methylenetetrahydrofolate Reductase (FADH2)In Situ HybridizationPregnancy in DiabeticsRisk FactorsUrinary Bladder, NeurogenicNotochordMutationAbnormalities, Severe TeratoidThymidine MonophosphateEmbryonic DevelopmentCleft LipAbortion, SpontaneousMethylenetetrahydrofolate Dehydrogenase (NAD+)Maternal Nutritional Physiological PhenomenaManebPhenotypeCleft PalateAcrocallosal SyndromeRiskLumbosacral RegionFormate-Tetrahydrofolate LigaseMorphogenesisHomozygoteGenotypeDeanolTranscription FactorsAnemia, MacrocyticTeratogens