Nasal BoneBone and BonesDown SyndromeNasal MucosaCrown-Rump LengthUltrasonography, PrenatalNuchal Translucency MeasurementPregnancy Trimester, FirstBone RemodelingPregnancy Trimester, SecondBone DensitySkull FracturesNasal PolypsNasal SeptumGestational AgePregnancyBone ResorptionMaternal AgeBone MarrowChorionic Villi SamplingNasal Lavage FluidChromosomes, Human, 16-18Chorionic Gonadotropin, beta Subunit, HumanPregnancy-Associated Plasma Protein-ANose Deformities, AcquiredBone NeoplasmsBone DevelopmentBone Marrow CellsBone DiseasesImaging, Three-DimensionalNoseNasal DecongestantsChromosomes, Human, 13-15Facial BonesBone RegenerationProspective StudiesBone MatrixObserver VariationBone Marrow TransplantationBone TransplantationPregnancy, High-RiskNasal SpraysFetal DiseasesFeasibility Studies