Birth RatePremature BirthPregnancyInfant, NewbornInfant, PrematureGestational AgeInfant, Low Birth WeightInfant MortalityObstetric Labor, PrematurePregnancy OutcomeLive BirthBirth WeightUnited StatesPregnancy in AdolescencePregnancy RatePregnancy ComplicationsFetal Membranes, Premature RupturePregnancy, MultipleMaternal AgeEmbryo TransferCerclage, CervicalFertilization in VitroMultiple Birth OffspringBirth CertificatesInfant, Premature, DiseasesReproductive Techniques, AssistedInfant, Small for Gestational AgeIllegitimacyStillbirthUterine Cervical IncompetenceVital StatisticsPrenatal CareChorioamnionitisCervical Length MeasurementTerm BirthCesarean SectionAbortion, SpontaneousFetal DeathRisk FactorsCohort StudiesTwinsDelivery, ObstetricCervix UteriInfant, Extremely PrematureTocolytic AgentsInfertility, FemalePregnancy Trimester, SecondOvulation InductionPregnancy, High-RiskOocyte RetrievalSperm Injections, IntracytoplasmicParturitionLabor, InducedEmbryo ImplantationParityAbortion, HabitualAmniotic FluidPregnancy Complications, InfectiousInfertilityRetrospective StudiesBirth OrderCryopreservationProspective StudiesReproductive Control AgentsFollicle Stimulating Hormone, HumanLogistic ModelsBirth IntervalsGamete Intrafallopian TransferSingle Embryo TransferMarital StatusPerinatal CareClomipheneRespiratory Distress Syndrome, NewbornInfant, Very Low Birth WeightSingle ParentOdds RatioMaternal ExposureFertility Agents, FemaleHydroxyprogesteronesDevelopmental DisabilitiesAdministration, IntravaginalAbortion, LegalVaginosis, BacterialCervical RipeningBronchopulmonary DysplasiaCongenital AbnormalitiesPregnancy Trimester, ThirdFetal Growth RetardationInsemination, Artificial, HomologousAfrican AmericansFertilityIntensive Care Units, NeonatalAbortion, InducedSocioeconomic FactorsNational Center for Health Statistics (U.S.)Child DevelopmentEmbryo Culture TechniquesIntensive Care, NeonatalPaternal AgePre-Eclampsia