Maternal AgeGestational AgeInfant, Small for Gestational AgePregnancyInfant, NewbornBirth WeightInfant, PrematurePregnancy OutcomeUltrasonography, PrenatalPremature BirthDown SyndromeBirth OrderInfant, Low Birth WeightPaternal AgePregnancy, High-RiskPregnancy ComplicationsPregnancy Trimester, SecondPregnancy Trimester, FirstParityRisk FactorsCrown-Rump LengthAmniocentesisFetal Growth RetardationPrenatal DiagnosisInfant, Premature, DiseasesCohort StudiesInfant MortalityPregnancy Trimester, ThirdObstetric Labor, PrematureFetal DeathCongenital AbnormalitiesProspective StudiesFetusBirth CertificatesFetal DiseasesFetal DevelopmentCesarean SectionInfant, Very Low Birth WeightTwinsAbortion, SpontaneousRetrospective StudiesStillbirthLogistic ModelsRegression AnalysisTrisomyPrenatal CareTerm BirthPregnancy, MultipleDelivery, ObstetricApgar ScoreAmniotic FluidMothersPre-EclampsiaNuchal Translucency MeasurementIntensive Care Units, NeonatalChild DevelopmentCase-Control StudiesPrenatal Exposure Delayed EffectsPerinatal MortalityChromosome DisordersOdds RatioNondisjunction, GeneticAneuploidyFetal MacrosomiaLive BirthMaternal ExposureChorionic Gonadotropin, beta Subunit, HumanLinear ModelsPlacentaFetal HeartGastroschisisReference ValuesPregnancy-Associated Plasma Protein-ASocioeconomic FactorsFetal WeightRetinopathy of PrematurityBody HeightAge FactorsLongitudinal StudiesFetal BloodInfant, Newborn, DiseasesCross-Sectional StudiesRegistriesPregnancy, TwinHernia, UmbilicalRespiratory Distress Syndrome, NewbornFetal MortalityTripletsDiabetes, GestationalHeart Rate, FetalFetal Membranes, Premature RuptureHypertension, Pregnancy-InducedUmbilical ArteriesMultivariate AnalysisObstetric Labor ComplicationsDevelopmental DisabilitiesPregnancy in DiabeticsFollow-Up StudiesModels, StatisticalUnited States