Fetal HeartHeart Rate, FetalHeartPopulation SurveillanceFetal MonitoringCardiotocographyHeart RateUltrasonography, PrenatalPregnancyHeart Defects, CongenitalSentinel SurveillanceEchocardiography, Four-DimensionalFetal MovementGestational AgeFetal DiseasesFetal DistressFetal HypoxiaUmbilical ArteriesFetusHeart FailurePublic Health SurveillanceHeart BlockCanrenoic AcidPregnancy Trimester, SecondHeart DiseasesEchocardiography, Three-DimensionalMagnetocardiographyUltrasonography, DopplerHeart TransplantationPregnancy Trimester, ThirdPregnancy Trimester, FirstLabor, ObstetricHeart ValvesMyocardiumInfant, NewbornProduct Surveillance, PostmarketingCardiac VolumeDisease OutbreaksImmunologic SurveillanceDisease NotificationProspective StudiesBradycardiaPregnancy OutcomeUnited StatesEchocardiographyFetal DevelopmentPrenatal DiagnosisAbortion, ThreatenedIncidencePublic Health InformaticsTime FactorsRisk FactorsSheepMaternal-Fetal ExchangeSensitivity and SpecificityBlood Flow VelocityApgar ScoreHeart AtriaMyocytes, CardiacFetal Growth RetardationEchocardiography, Doppler, ColorMyocardial ContractionEpidemiological MonitoringHemodynamicsPregnancy ComplicationsBehavioral Risk Factor Surveillance SystemRetrospective StudiesPerinatologyCrown-Rump LengthElectronics, MedicalReproducibility of ResultsPregnancy, High-RiskHeart SeptumAnalgesia, ObstetricalPlacental CirculationAnesthesia, ObstetricalFeasibility StudiesUltrasonography, Doppler, ColorCommunicable Diseases, EmergingCardiomegalyHeart AuscultationTocolytic AgentsCesarean SectionHeart Arrest, InducedDown SyndromeSEER ProgramPrevalenceHeart Function TestsUmbilical CordSheep, DomesticSufentanilBioterrorismFetal DeathSeasonsInfluenza, HumanUltrasonographyCommunicable DiseasesPredictive Value of TestsMyocardial IschemiaTachycardia