Down SyndromeSyndromeChromosomes, Human, Pair 21Prenatal DiagnosisTrisomyChild WelfareMaternal AgeDisabled ChildrenMetabolic Syndrome XChild BehaviorPregnancy Trimester, SecondPregnancyEstriolInfant, NewbornAmniocentesisLeukemia, Megakaryoblastic, AcuteNephrotic SyndromeIntellectual DisabilityFetal DiseasesChromosomes, Human, 21-22 and YParentsAbortion, EugenicSjogren's SyndromeChild Behavior DisordersChild Health ServicesKaryotypingAbnormalities, MultipleTurner SyndromeChild RearingRisk FactorsChild Languagealpha-FetoproteinsChild, InstitutionalizedPrevalenceChild PsychologyCase-Control StudiesNasal BoneAge FactorsRetrospective StudiesNuchal Translucency MeasurementNondisjunction, GeneticUltrasonography, PrenatalPregnancy, High-RiskChild of Impaired ParentsWilliams SyndromeHeart Defects, CongenitalPregnancy Trimester, FirstProspective StudiesDental Care for ChildrenChild, OrphanedMyelodysplastic SyndromesPhenotypePregnancy-Associated Plasma Protein-AChorionic Gonadotropin, beta Subunit, HumanTreatment OutcomeFollow-Up StudiesFalse Positive ReactionsPaternal AgeCushing SyndromeTime FactorsMothersDisease Models, AnimalChromosome DisordersCross-Sectional StudiesPolycystic Ovary SyndromeAcute Coronary SyndromeChild Nutrition DisordersChild Nutritional Physiological PhenomenaDiGeorge SyndromeQuestionnairesBiological MarkersLanguage Development DisordersStanford-Binet TestCraniofacial AbnormalitiesPrader-Willi SyndromeSeverity of Illness IndexBrainChild MortalityHorner SyndromeMutationLearning DisordersLong QT SyndromeHemolytic-Uremic SyndromeGenetic TestingGestational AgeHeart Septal DefectsParent-Child RelationsGuillain-Barre SyndromeReference ValuesPedigreeTourette SyndromeIncidenceMotor SkillsAutistic DisorderLanguage DisordersLanguage DevelopmentAlzheimer DiseaseDuodenal ObstructionIntelligenceCompartment Syndromes