TwinsDiseases in TwinsPregnancyTwins, MonozygoticTwins, ConjoinedTwins, DizygoticPregnancy OutcomePregnancy ComplicationsPregnancy, AnimalPregnancy, TwinPregnancy, EctopicPregnancy, MultipleTwin Studies as TopicPregnancy Trimester, FirstPregnancy Trimester, ThirdPregnancy RatePregnancy Complications, CardiovascularPregnancy TrimestersPregnancy TestsPregnancy Trimester, SecondGestational AgePregnancy in DiabeticsPrenatal Exposure Delayed EffectsPregnancy, TubalPregnancy Complications, InfectiousPregnancy Complications, NeoplasticInfant, NewbornPregnancy in AdolescenceAbortion, SpontaneousFetal DeathMaternal-Fetal ExchangePregnancy, High-RiskFetusPregnancy ProteinsPregnancy, UnplannedPlacentaPregnancy, UnwantedFetal DiseasesMaternal ExposureBirth WeightPregnancy Complications, HematologicUterusUltrasonography, PrenatalPre-EclampsiaPregnancy, ProlongedPregnancy Reduction, MultifetalEmbryo TransferFertilization in VitroAbortion, InducedFetal Growth RetardationFetofetal TransfusionPregnancy Complications, ParasiticEmbryo ImplantationPregnancy, AbdominalAbnormalities, Drug-InducedTripletsParityPrenatal CarePregnancy MaintenanceMaternal AgeCesarean SectionCongenital AbnormalitiesLactationObstetric Labor, PrematurePremature BirthRisk FactorsDelivery, ObstetricHypertension, Pregnancy-InducedFetal TherapiesFetal DevelopmentProgesteroneAbortion, TherapeuticInfertility, FemaleCohort StudiesAmniotic FluidProspective StudiesLabor, ObstetricPrenatal DiagnosisDiabetes, GestationalReproductive Techniques, AssistedInfant, Low Birth WeightFertilitySperm Injections, IntracytoplasmicPlacenta DiseasesEmbryonic and Fetal DevelopmentChorionSheepTrophoblastsDeciduaChorionic GonadotropinFetal BloodRetrospective StudiesInsemination, ArtificialStillbirthTime FactorsPrenatal Nutritional Physiological PhenomenaFetal WeightParturitionInfectious Disease Transmission, VerticalAbortion, Habitual