Pregnancy TestsPregnancyPregnancy, EctopicPregnancy OutcomeFalse Positive ReactionsPregnancy ComplicationsPregnancy, AnimalPregnancy Trimester, FirstPregnancy RatePregnancy Trimester, ThirdPregnancy Complications, CardiovascularPregnancy TrimestersPregnancy, MultiplePregnancy Trimester, SecondPregnancy in DiabeticsPregnancy, TubalPregnancy Complications, NeoplasticPregnancy in AdolescencePregnancy Complications, InfectiousAbortion, SpontaneousPregnancy ProteinsPregnancy, UnplannedFalse Negative ReactionsPregnancy, High-RiskGestational AgePregnancy, UnwantedInfant, NewbornPregnancy Complications, HematologicSensitivity and SpecificityPregnancy, ProlongedPre-EclampsiaPregnancy, TwinPlacentaFetal DeathUltrasonography, PrenatalAbortion, InducedPregnancy, AbdominalUterusPregnancy Complications, ParasiticPregnancy MaintenanceEmbryo ImplantationAlgorithmsEmbryo TransferPrenatal CareFertilization in VitroMaternal-Fetal ExchangeParityPrenatal DiagnosisPrenatal Exposure Delayed EffectsMaternal AgeBirth WeightReproducibility of ResultsPregnancy Reduction, MultifetalProspective StudiesHypertension, Pregnancy-InducedCesarean SectionFetal Growth RetardationProgesteroneFetal DiseasesFetusPremature BirthChorionic GonadotropinInfertility, FemaleAbnormalities, Drug-InducedLactationRetrospective StudiesFetal DevelopmentDeciduaChorionic Gonadotropin, beta Subunit, HumanLabor, ObstetricObstetric Labor, PrematureCongenital AbnormalitiesTwinsRisk FactorsMaternal ExposureDiabetes, GestationalAbortion, TherapeuticPregnancy Tests, ImmunologicTrophoblastsAbortion, HabitualPredictive Value of TestsTime FactorsAbortifacient Agents, NonsteroidalInsemination, ArtificialDelivery, ObstetricPuerperal DisordersCohort StudiesEndometriumSperm Injections, IntracytoplasmicFertilityInfant, Low Birth WeightPreconception CarePlacenta DiseasesAmniotic FluidInfertilityPregnant WomenStillbirthGravidityReproductive Techniques, AssistedSoftware