Cervical Length MeasurementCervix UteriObstetric Labor, PrematureCervical RipeningPregnancy Trimester, SecondPremature BirthPregnancy Trimester, ThirdUltrasonography, PrenatalGestational AgePregnancyTwinsUterine Cervical IncompetenceCerclage, CervicalPregnancy, ProlongedAxial Length, EyeLabor, InducedLabor OnsetNasal BoneInterferometryGravidityPregnancy, High-RiskBiometryCrown-Rump LengthTocolysisReproducibility of ResultsAbortion, ThreatenedPregnancy Trimester, FirstTelomere HomeostasisObserver VariationTelomereProspective StudiesParityPregnancy, MultipleCesarean SectionDelivery, ObstetricPredictive Value of TestsTelomere ShorteningBody Weights and MeasuresSensitivity and SpecificityFetal Membranes, Premature RuptureHydroxyprogesteronesPregnancy OutcomeROC CurveReference ValuesTripletsPolyhydramniosAnterior ChamberAnthropometryLabor Stage, FirstUterine ContractionPessariesInfant, NewbornVaginaAdministration, IntravaginalAmniocentesis