TwinsPregnancyDiseases in TwinsPregnancy OutcomePregnancy ComplicationsTwins, MonozygoticPregnancy, AnimalTwins, ConjoinedTwins, DizygoticPregnancy, EctopicPregnancy Trimester, FirstPregnancy, MultiplePregnancy RatePregnancy Trimester, ThirdPregnancy, TwinPregnancy Complications, CardiovascularPregnancy TrimestersPregnancy TestsPregnancy Trimester, SecondPregnancy in DiabeticsPregnancy, TubalPregnancy Complications, NeoplasticPregnancy in AdolescencePregnancy Complications, InfectiousTwin Studies as TopicAbortion, SpontaneousGestational AgePregnancy ProteinsPregnancy, High-RiskPregnancy, UnplannedPregnancy, UnwantedInfant, NewbornPregnancy Complications, HematologicFetal DeathPlacentaPre-EclampsiaPregnancy, ProlongedUltrasonography, PrenatalAbortion, InducedUterusPregnancy, AbdominalEmbryo TransferFertilization in VitroPregnancy Complications, ParasiticBirth WeightPregnancy MaintenancePregnancy Reduction, MultifetalEmbryo ImplantationPrenatal CareParityMaternal-Fetal ExchangePrenatal Exposure Delayed EffectsMaternal AgeCesarean SectionFetal Growth RetardationHypertension, Pregnancy-InducedPremature BirthProgesteroneCongenital AbnormalitiesFetal DevelopmentObstetric Labor, PrematureTripletsInfertility, FemaleFetusLactationPrenatal DiagnosisAbnormalities, Drug-InducedLabor, ObstetricDelivery, ObstetricDeciduaRisk FactorsAbortion, TherapeuticChorionic GonadotropinFetal DiseasesProspective StudiesDiabetes, GestationalMaternal ExposureSperm Injections, IntracytoplasmicReproductive Techniques, AssistedTrophoblastsFetofetal TransfusionInsemination, ArtificialInfant, Low Birth WeightAbortion, HabitualFertilityAbortifacient Agents, NonsteroidalCohort StudiesAmniotic FluidPuerperal DisordersPlacenta DiseasesEndometriumInfertilityStillbirthPreconception CareGravidityPregnant WomenRetrospective StudiesChorionic Gonadotropin, beta Subunit, HumanParturitionOvulation Induction