Fetal HeartHeart Rate, FetalHeartHeart RateFetal MonitoringCardiotocographyHeart Defects, CongenitalUltrasonography, PrenatalHeart FailurePregnancyEchocardiography, Four-DimensionalHeart DiseasesFetal MovementGestational AgeFetal DiseasesHeart TransplantationFetal HypoxiaFetal DistressHeart BlockHeart ValvesUmbilical ArteriesFetusMyocardiumHeart AtriaCanrenoic AcidPregnancy Trimester, SecondEchocardiography, Three-DimensionalMagnetocardiographyUltrasonography, DopplerPregnancy Trimester, ThirdPregnancy Trimester, FirstEchocardiographyMyocardial ContractionLabor, ObstetricMyocytes, CardiacCardiac VolumeHeart Arrest, InducedHemodynamicsHeart Function TestsProspective StudiesHeart SeptumMyocardial IschemiaBradycardiaPregnancy OutcomeCardiomegalyFetal DevelopmentBlood Flow VelocityPrenatal DiagnosisAbortion, ThreatenedTime FactorsSheepMaternal-Fetal ExchangeCoronary DiseaseEchocardiography, Doppler, ColorInfant, NewbornApgar ScoreCardiac Output, LowFetal Growth RetardationVentricular Function, LeftRisk FactorsHeart, ArtificialHeart Failure, SystolicPerfusionPerinatologyCrown-Rump LengthCardiomyopathy, DilatedMyocardial InfarctionElectronics, MedicalHeart InjuriesCardiotonic AgentsPregnancy ComplicationsRheumatic Heart DiseaseStroke VolumeCardiomyopathiesMyocardial Reperfusion InjuryAnalgesia, ObstetricalPregnancy, High-RiskHeart ArrestTachycardiaSensitivity and SpecificityPlacental CirculationAnesthesia, ObstetricalHeart Valve ProsthesisRats, Sprague-DawleyVentricular Dysfunction, LeftReference ValuesReproducibility of ResultsAdrenergic beta-AntagonistsHeart Failure, DiastolicEchocardiography, DopplerSystoleAmerican Heart AssociationTocolytic AgentsHeart AuscultationFeasibility StudiesDown SyndromeVentricular RemodelingSheep, DomesticUmbilical CordDogs