TwinsDiseases in TwinsTwins, MonozygoticPregnancyTwins, ConjoinedTwins, DizygoticPregnancy OutcomePregnancy ComplicationsPregnancy, AnimalPregnancy, TwinPregnancy, EctopicPregnancy, MultipleTwin Studies as TopicPregnancy Trimester, FirstPregnancy RatePregnancy Trimester, ThirdPregnancy Complications, CardiovascularPregnancy TrimestersPregnancy TestsPregnancy Trimester, SecondPregnancy in DiabeticsPregnancy, TubalPregnancy Complications, NeoplasticPregnancy in AdolescenceGestational AgePregnancy Complications, InfectiousAbortion, SpontaneousInfant, NewbornPregnancy, High-RiskPregnancy ProteinsPregnancy, UnplannedFetal DeathPregnancy, UnwantedUltrasonography, PrenatalPlacentaPregnancy Complications, HematologicFertilization in VitroEmbryo TransferPre-EclampsiaPregnancy, ProlongedPregnancy Reduction, MultifetalBirth WeightUterusAbortion, InducedEmbryo ImplantationPregnancy, AbdominalTripletsPregnancy Complications, ParasiticPrenatal CareFetofetal TransfusionParityPregnancy MaintenanceMaternal AgeCesarean SectionMaternal-Fetal ExchangePrenatal Exposure Delayed EffectsInfertility, FemaleFetal Growth RetardationRisk FactorsReproductive Techniques, AssistedPremature BirthCongenital AbnormalitiesObstetric Labor, PrematureProspective StudiesSperm Injections, IntracytoplasmicHypertension, Pregnancy-InducedDelivery, ObstetricCohort StudiesFetal DevelopmentPrenatal DiagnosisProgesteroneFetusRetrospective StudiesInfertilityLactationAbnormalities, Drug-InducedFetal DiseasesLabor, ObstetricFertilityChorionTime FactorsDeciduaInsemination, ArtificialChorionic GonadotropinInfant, Low Birth WeightAbortion, TherapeuticMaternal ExposureAbortion, HabitualDiabetes, GestationalLive BirthAmniotic FluidTrophoblastsPlacenta DiseasesOvulation InductionGravidityAbortifacient Agents, NonsteroidalStillbirthEndometriumPuerperal DisordersParturition