Fetal HeartHeart Rate, FetalHeartFetal MonitoringCardiotocographyHeart RateUltrasonography, PrenatalHeart Defects, CongenitalPregnancyEchocardiography, Four-DimensionalFetal MovementGestational AgeFetal DiseasesFetal DistressFetal HypoxiaUmbilical ArteriesFetusHeart FailureHeart BlockCanrenoic AcidPregnancy Trimester, SecondEchocardiography, Three-DimensionalHeart DiseasesMagnetocardiographyUltrasonography, DopplerHeart TransplantationPregnancy Trimester, FirstPregnancy Trimester, ThirdHeart ValvesLabor, ObstetricMyocardiumCardiac VolumeBradycardiaPregnancy OutcomeEchocardiographyFetal DevelopmentAbortion, ThreatenedPrenatal DiagnosisProspective StudiesMaternal-Fetal ExchangeBlood Flow VelocitySheepHeart AtriaApgar ScoreMyocytes, CardiacFetal Growth RetardationEchocardiography, Doppler, ColorInfant, NewbornSensitivity and SpecificityCrown-Rump LengthMyocardial ContractionHemodynamicsPerinatologyReproducibility of ResultsElectronics, MedicalPregnancy, High-RiskPregnancy ComplicationsHeart SeptumAnalgesia, ObstetricalPlacental CirculationTomography, X-Ray ComputedTime FactorsAnesthesia, ObstetricalCardiomegalyUltrasonography, Doppler, ColorHeart AuscultationTocolytic AgentsFeasibility StudiesImage Processing, Computer-AssistedHeart Arrest, InducedDown SyndromeHeart Function TestsUmbilical CordSheep, DomesticCesarean SectionUltrasonographySufentanilReference ValuesRetrospective StudiesMyocardial IschemiaTachycardiaEmbryonic and Fetal DevelopmentRisk FactorsHeart VentriclesFetal DeathPredictive Value of TestsAnesthesia, EpiduralPregnancy in DiabeticsData DisplayNuchal Translucency MeasurementObstetricsEchocardiography, DopplerCoronary DiseaseMeconiumDelivery, ObstetricChromosome DisordersImage Interpretation, Computer-AssistedObstetric Labor ComplicationsObserver VariationVascular Malformations