Down SyndromeSyndromeChromosomes, Human, Pair 21Prenatal DiagnosisTrisomyMaternal AgeMetabolic Syndrome XPregnancy Trimester, SecondInfant, NewbornPregnancyEstriolAmniocentesisLeukemia, Megakaryoblastic, AcuteNephrotic SyndromeFetal DiseasesChromosomes, Human, 21-22 and YRisk FactorsIntellectual DisabilityAbortion, EugenicSjogren's SyndromeKaryotypingTurner SyndromeAbnormalities, MultiplePrecursor Cell Lymphoblastic Leukemia-Lymphomaalpha-FetoproteinsCase-Control StudiesNasal BoneNuchal Translucency MeasurementUltrasonography, PrenatalNondisjunction, GeneticChild DevelopmentPregnancy, High-RiskPregnancy Trimester, FirstPrevalenceAge FactorsWilliams SyndromePhenotypeParentsRetrospective StudiesPaternal AgeMyelodysplastic SyndromesPregnancy-Associated Plasma Protein-AChorionic Gonadotropin, beta Subunit, HumanCohort StudiesChild AbuseCushing SyndromeDisease Models, AnimalHeart Defects, CongenitalFollow-Up StudiesChromosome DisordersFalse Positive ReactionsProspective StudiesPolycystic Ovary SyndromeAcute Coronary SyndromeAdult Survivors of Child AbuseMutationDiGeorge SyndromeTime FactorsPedigreePrader-Willi SyndromeChild Abuse, SexualCraniofacial AbnormalitiesBrainHorner SyndromeTreatment OutcomeGestational AgeLong QT SyndromeGenetic TestingStanford-Binet TestBiological MarkersLongitudinal StudiesIncidenceHemolytic-Uremic SyndromeTourette SyndromeHeart Septal DefectsQuestionnairesGuillain-Barre SyndromeChromosome AberrationsAlzheimer DiseaseDuodenal ObstructionDevelopmental DisabilitiesAge of OnsetCompartment SyndromesGATA1 Transcription FactorObesityChorionic GonadotropinMosaicismMothersAntiphospholipid SyndromeNeckSurvivorsCross-Sectional StudiesKlinefelter SyndromeGenotypeIntelligencePorcine Reproductive and Respiratory SyndromeSeverity of Illness IndexCongenital AbnormalitiesReye SyndromeAbortion, Induced