Maternal AgeBirth WeightPregnancyBirth OrderInfant, NewbornPremature BirthPaternal AgeInfant, Low Birth WeightDown SyndromeBirth RatePregnancy OutcomePregnancy, High-RiskBirth CertificatesGestational AgeParityAmniocentesisPregnancy ComplicationsCongenital AbnormalitiesRisk FactorsPrenatal DiagnosisInfant MortalityBirth IntervalsPregnancy Trimester, FirstTrisomyCesarean SectionAbortion, SpontaneousFetal DeathDelivery of Health CarePrenatal CareMothersNondisjunction, GeneticHealth PersonnelCohort StudiesDelivery, ObstetricUnited StatesPregnancy, MultipleCrown-Rump LengthPregnancy Trimester, SecondAneuploidyInfant, Small for Gestational AgeUltrasonography, PrenatalNuchal Translucency MeasurementChromosome DisordersSocioeconomic FactorsStillbirthMultiple Birth OffspringRetrospective StudiesLogistic ModelsChorionic Gonadotropin, beta Subunit, HumanHernia, UmbilicalGastroschisisPerinatal MortalityReproductive Techniques, AssistedPregnancy in AdolescenceObstetric Labor ComplicationsFertilization in VitroPrenatal Exposure Delayed EffectsMaternal ExposurePregnancy-Associated Plasma Protein-AProspective StudiesOdds RatioRegistriesHealthcare DisparitiesHealth Care CostsObstetric Labor, PrematurePreimplantation DiagnosisAge FactorsQuestionnairesFetal DiseasesUnited States Agency for Healthcare Research and QualityBreast FeedingPrevalencePerinatal CareSex RatioRegression AnalysisCase-Control StudiesEducational StatusCross-Sectional StudiesLive BirthAbortion, EugenicMarital StatusDenmarkChromosome AberrationsSocial ClassSwedenApgar ScoreRiskNorwayBirth InjuriesPolar BodiesHealth Services AccessibilityIncidenceChromosomes, Human, Pair 21Great BritainBrazilChorionic Villi SamplingEnglandFetal MacrosomiaEmbryo TransferTwins