Pregnancy, TwinTwinsDiseases in TwinsPregnancy, MultiplePregnancyTwins, MonozygoticTwins, DizygoticPregnancy OutcomeTwins, ConjoinedPregnancy ComplicationsFetofetal TransfusionPregnancy, AnimalFetal DeathGestational AgePregnancy Trimester, FirstUltrasonography, PrenatalChorionPregnancy, EctopicPregnancy Reduction, MultifetalPregnancy Trimester, SecondTwinning, MonozygoticPregnancy Trimester, ThirdPregnancy RatePregnancy Complications, CardiovascularPregnancy TestsTwin Studies as TopicEmbryo TransferInfant, NewbornFertilization in VitroCesarean SectionPregnancy, High-RiskObstetric Labor, PrematurePregnancy Complications, NeoplasticTripletsFetal Growth RetardationSingle Umbilical ArteryAbortion, SpontaneousHydatidiform MolePremature BirthPre-EclampsiaMaternal AgePregnancy TrimestersBirth WeightPrenatal DiagnosisPlacentaReproductive Techniques, AssistedDelivery, ObstetricFetoscopyPregnancy in DiabeticsSperm Injections, IntracytoplasmicPregnancy, TubalPregnancy ProteinsAmniocentesisCongenital AbnormalitiesFetal WeightCrown-Rump LengthFetal DiseasesNuchal CordPregnancy in AdolescencePregnancy Complications, InfectiousMaternal Serum Screening TestsPerinatal MortalityParityPregnancy, TripletPolyhydramniosOocyte DonationHypertension, Pregnancy-InducedFetal DevelopmentUmbilical ArteriesRetrospective StudiesAmnionPregnancy, UnplannedEmbryo ImplantationChorionic Gonadotropin, beta Subunit, HumanPregnancy, UnwantedBirth OrderCervix UteriUmbilical CordAmniotic FluidUterusAbortion, EugenicReproductive TechniquesFetal ViabilityLabor, ObstetricFetusProspective StudiesHydrops FetalisSingle Embryo TransferPregnancy Complications, HematologicChorionic Villi SamplingInfant, Small for Gestational AgeInsemination, ArtificialRisk FactorsInfertility, FemaleArteriovenous AnastomosisPregnancy, ProlongedProgestinsInfant MortalityNuchal Translucency MeasurementTerm Birth