TrisomyMaternal AgeDown SyndromePregnancyChromosome DisordersPrenatal DiagnosisChromosomes, Human, Pair 18Pregnancy, High-RiskKaryotypingPaternal AgeAmniocentesisNuchal Translucency MeasurementChromosomes, Human, Pair 21Pregnancy Trimester, FirstNondisjunction, GeneticChromosomes, Human, Pair 13Chorionic Gonadotropin, beta Subunit, HumanBirth OrderInfant, NewbornChromosomes, Human, 16-18Ultrasonography, PrenatalMosaicismPregnancy Trimester, SecondAneuploidyGestational AgeChromosome AberrationsPregnancy-Associated Plasma Protein-ACrown-Rump LengthAbnormalities, MultiplePregnancy OutcomeFetal DiseasesChromosomes, Human, 13-15Chromosomes, Human, 21-22 and YParityNasal BoneAbortion, SpontaneousCongenital AbnormalitiesChromosomes, Human, 6-12 and XBirth WeightChorionic Villi SamplingPregnancy ComplicationsNeckIn Situ Hybridization, FluorescenceFetal DeathChromosomes, Human, 19-20Abortion, EugenicRisk FactorsTranslocation, GeneticHernia, UmbilicalChromosome BandingBirth CertificatesDermatoglyphicsCesarean SectionChromosomes, Human, Pair 8Infant, Low Birth WeightMothersPreimplantation DiagnosisMonosomyInfant MortalityPregnancy, MultiplePremature BirthChromosomes, Human, Pair 12GastroschisisChromosomes, Human, 4-5Chromosomes, Human, Pair 7FetusSex Chromosome AberrationsFertilization in VitroRetrospective StudiesPrenatal CareLive BirthStillbirthTurner SyndromePerinatal MortalityBirth IntervalsBirth RateCytogenetic AnalysisReproductive Techniques, AssistedInfant, Small for Gestational AgeProspective StudiesCase-Control StudiesTwinsCohort StudiesFetal Growth RetardationMeiosisChromosomes, Human, 1-3Pregnancy in AdolescenceIntellectual DisabilityEstriolPolar BodiesPregnancy Trimester, ThirdLogistic ModelsDelivery, ObstetricFalse Positive ReactionsHeart Defects, CongenitalSex RatioChromosomes, HumanObstetric Labor ComplicationsHeart Rate, FetalGenetic Counseling