Neural Tube DefectsNeural TubeAnencephalySpinal DysraphismFolic AcidSpina Bifida OccultaNeurulationSpina Bifida CysticaEncephalocelePregnancyMeningomyeloceleVitamin B ComplexPreconception CarePrenatal DiagnosisFood, FortifiedCongenital AbnormalitiesFolic Acid DeficiencyAbortion, Therapeuticalpha-FetoproteinsNeural CrestInfant, NewbornNervous SystemAir Pollution, RadioactiveAmniocentesisPrenatal CareEmbryo, MammalianAmniotic FluidDietary SupplementsMouth AbnormalitiesIrelandGene Expression Regulation, DevelopmentalCentral Nervous SystemFetal DeathChick EmbryoFlourHomocysteineVitamin B 12TailZinebPaired Box Transcription FactorsMethylenetetrahydrofolate Reductase (NADPH2)Mice, Mutant StrainsEmbryonic and Fetal DevelopmentVitamin B 12 DeficiencyBody PatterningMethylenetetrahydrofolate Dehydrogenase (NADP)NotochordIn Situ HybridizationVitaminsFetal DiseasesPregnancy in DiabeticsEmbryonic DevelopmentManebPregnancy ComplicationsFormate-Tetrahydrofolate LigaseGestational AgeThymidine MonophosphateDeanolTeratogensMorphogenesisPollen TubeMutationCase-Control StudiesFolate Receptor 1Maternal ExposurePrenatal Nutritional Physiological PhenomenaAbnormalities, Drug-InducedAbortion, InducedTetrahydrofolatesAbnormalities, MultiplePhenotypeCleft LipTranscription FactorsHeart Defects, CongenitalTranscobalaminsBreadMolecular Sequence DataCraniofacial AbnormalitiesHomeodomain ProteinsPregnancy Trimester, SecondPregnancy Trimester, FirstThiocholineMeningoceleFolate Receptors, GPI-AnchoredRisk FactorsPrevalenceHydrocephalusEstriolQuailDown SyndromeMaternal Nutritional Physiological PhenomenaRiskCerebral AqueductMice, Neurologic MutantsCleft PalateHomozygoteTrisomy