Pregnancy RatePregnancyTwinsDiseases in TwinsEmbryo TransferTwins, MonozygoticFertilization in VitroTwins, ConjoinedTwins, DizygoticPregnancy OutcomePregnancy ComplicationsPregnancy, AnimalPregnancy, TwinPregnancy, EctopicTwin Studies as TopicPregnancy, MultiplePregnancy Trimester, FirstPregnancy Trimester, ThirdPregnancy Complications, CardiovascularPregnancy TrimestersPregnancy TestsPregnancy Trimester, SecondPregnancy in DiabeticsPregnancy, TubalPregnancy Complications, NeoplasticPregnancy in AdolescenceGestational AgePregnancy Complications, InfectiousAbortion, SpontaneousPregnancy, High-RiskPregnancy ProteinsInfant, NewbornPregnancy, UnplannedPregnancy, UnwantedFetal DeathPregnancy Complications, HematologicUltrasonography, PrenatalPlacentaPre-EclampsiaPregnancy, ProlongedPregnancy Reduction, MultifetalBirth WeightAbortion, InducedUterusPregnancy, AbdominalTripletsPregnancy Complications, ParasiticEmbryo ImplantationFetofetal TransfusionPregnancy MaintenancePrenatal CareParityMaternal AgeMaternal-Fetal ExchangeCesarean SectionPrenatal Exposure Delayed EffectsFetal Growth RetardationPremature BirthCongenital AbnormalitiesHypertension, Pregnancy-InducedObstetric Labor, PrematureFetal DevelopmentDelivery, ObstetricFetusProgesteroneRisk FactorsInfertility, FemalePrenatal DiagnosisReproductive Techniques, AssistedLactationLabor, ObstetricSperm Injections, IntracytoplasmicFetal DiseasesAbnormalities, Drug-InducedChorionProspective StudiesCohort StudiesDeciduaAbortion, TherapeuticChorionic GonadotropinInfant, Low Birth WeightDiabetes, GestationalMaternal ExposureInsemination, ArtificialFertilityAmniotic FluidTrophoblastsPlacenta DiseasesRetrospective StudiesAbortion, HabitualAbortifacient Agents, NonsteroidalStillbirthPuerperal DisordersInfertilityGravidityEndometriumPreconception CarePregnant WomenChorionic Gonadotropin, beta Subunit, HumanLive Birth