Gestational AgeInfant, Small for Gestational AgeInfant, NewbornPregnancyInfant, PrematureBirth WeightEthnic GroupsUltrasonography, PrenatalPremature BirthPregnancy OutcomeFetal Growth RetardationInfant, Premature, DiseasesInfant, Low Birth WeightEuropean Continental Ancestry GroupHispanic AmericansPregnancy Trimester, SecondContinental Population GroupsPregnancy Trimester, ThirdFetusRisk FactorsFetal DevelopmentPregnancy ComplicationsInfant, Very Low Birth WeightObstetric Labor, PrematurePregnancy Trimester, FirstCrown-Rump LengthAfrican AmericansAmniotic FluidIntensive Care Units, NeonatalProspective StudiesCohort StudiesUnited StatesMaternal AgeTerm BirthFetal HeartApgar ScoreFetal DiseasesInfant MortalityRetrospective StudiesRetinopathy of PrematurityAfrican Continental Ancestry GroupTwinsRespiratory Distress Syndrome, NewbornChild DevelopmentCross-Sectional StudiesPre-EclampsiaReference ValuesLogistic ModelsUmbilical ArteriesPlacentaFetal DeathStillbirthSocioeconomic FactorsDelivery, ObstetricBronchopulmonary DysplasiaPrenatal DiagnosisIntensive Care, NeonatalBirth CertificatesRegression AnalysisInfant, Newborn, DiseasesInfant, Extremely Low Birth WeightFetal WeightPrenatal CareCase-Control StudiesSex FactorsCesarean SectionInfant, Extremely PrematureParityFetal BloodCaliforniaEmbryonic and Fetal DevelopmentDevelopmental DisabilitiesFetal MacrosomiaFetal Organ MaturityLinear ModelsBody HeightChorioamnionitisFetal Membranes, Premature RupturePrevalenceAsian AmericansOdds RatioPregnancy TrimestersAnthropometryFetal MortalityAge FactorsCongenital AbnormalitiesUmbilical CordHeart Rate, FetalHeadIncidenceFetal MonitoringEchoencephalographyMothersTripletsMaternal ExposureMultivariate AnalysisPrenatal Exposure Delayed EffectsPregnancy, TwinNeonatal ScreeningLongitudinal Studies