TrisomyDown SyndromeChromosomes, Human, Pair 18KaryotypingChromosome DisordersChromosomes, Human, 16-18Chromosomes, Human, Pair 21Chromosomes, Human, Pair 13Prenatal DiagnosisMosaicismAbnormalities, MultipleNuchal Translucency MeasurementChorionic Gonadotropin, beta Subunit, HumanChromosomes, Human, 13-15Nondisjunction, GeneticChromosomes, Human, 6-12 and XChromosome AberrationsPregnancy Trimester, FirstUltrasonography, PrenatalMaternal AgeFetal DiseasesPregnancy-Associated Plasma Protein-APregnancy Trimester, SecondPregnancyNasal BoneChromosomes, Human, 21-22 and YAneuploidyChromosome BandingDermatoglyphicsPregnancy, High-RiskAmniocentesisCrown-Rump LengthIn Situ Hybridization, FluorescenceChromosomes, Human, Pair 8Translocation, GeneticMonosomyChromosomes, Human, Pair 12Chromosomes, Human, 19-20Chorionic Villi SamplingChromosomes, Human, 4-5Chromosomes, Human, Pair 7NeckGestational AgeChromosomes, Human, 1-3Intellectual DisabilityInfant, NewbornCytogenetic AnalysisCytogeneticsForeheadAbortion, EugenicFetus