TrisomyDown SyndromeKaryotypingChromosomes, Human, Pair 18Chromosome DisordersChromosomes, Human, 16-18Chromosomes, Human, Pair 21Chromosomes, Human, Pair 13MosaicismPrenatal DiagnosisAbnormalities, MultipleNuchal Translucency MeasurementChorionic Gonadotropin, beta Subunit, HumanChromosomes, Human, 13-15Nondisjunction, GeneticChromosome AberrationsChromosomes, Human, 6-12 and XPregnancy Trimester, FirstMaternal AgeUltrasonography, PrenatalFetal DiseasesChromosomes, Human, 21-22 and YPregnancy-Associated Plasma Protein-APregnancy Trimester, SecondPregnancyNasal BoneAneuploidyChromosome BandingDermatoglyphicsAmniocentesisPregnancy, High-RiskIn Situ Hybridization, FluorescenceCrown-Rump LengthTranslocation, GeneticChromosomes, Human, Pair 8MonosomyChromosomes, Human, Pair 12Chromosomes, Human, Pair 7Chromosomes, Human, 19-20Chorionic Villi SamplingChromosomes, Human, 4-5NeckGestational AgeIntellectual DisabilityChromosomes, Human, 1-3Infant, NewbornSex Chromosome AberrationsCytogenetic AnalysisFetusCytogeneticsForeheadAbortion, EugenicSyndrome