TwinsDiseases in TwinsTwins, MonozygoticPregnancyTwins, ConjoinedTwins, DizygoticPregnancy ComplicationsPregnancy OutcomePregnancy, AnimalPostoperative ComplicationsPregnancy, TwinPregnancy, EctopicPregnancy, MultipleTwin Studies as TopicPregnancy Trimester, FirstPregnancy Trimester, ThirdPregnancy Complications, CardiovascularPregnancy RatePregnancy TrimestersPregnancy TestsPregnancy Trimester, SecondPregnancy in DiabeticsPregnancy, TubalPregnancy Complications, NeoplasticPregnancy Complications, InfectiousGestational AgePregnancy in AdolescenceInfant, NewbornRetrospective StudiesAbortion, SpontaneousPregnancy, High-RiskTreatment OutcomeFetal DeathPregnancy ProteinsPregnancy, UnplannedPregnancy, UnwantedPregnancy Complications, HematologicIntraoperative ComplicationsRisk FactorsPre-EclampsiaUltrasonography, PrenatalProspective StudiesPlacentaPregnancy, ProlongedPregnancy Reduction, MultifetalBirth WeightTime FactorsAbortion, InducedFertilization in VitroEmbryo TransferUterusFollow-Up StudiesPregnancy, AbdominalCesarean SectionTripletsPrenatal CarePregnancy Complications, ParasiticParityFetofetal TransfusionEmbryo ImplantationFetal Growth RetardationPregnancy MaintenanceMaternal AgeCohort StudiesMaternal-Fetal ExchangeObstetric Labor ComplicationsPrenatal Exposure Delayed EffectsDiabetes ComplicationsPremature BirthDelivery, ObstetricHypertension, Pregnancy-InducedCongenital AbnormalitiesObstetric Labor, PrematureFetal DevelopmentInfertility, FemaleFetusPrenatal DiagnosisReproductive Techniques, AssistedIncidenceProgesteroneFetal DiseasesLabor, ObstetricRisk AssessmentLactationDiabetes, GestationalAbnormalities, Drug-InducedSperm Injections, IntracytoplasmicAbortion, TherapeuticReoperationInfant, Low Birth WeightPlacenta DiseasesPuerperal DisordersChorionLaparoscopyDeciduaChorionic GonadotropinStillbirthAmniotic FluidMaternal ExposureTrophoblasts