Fetal DiseasesPrimary PreventionSecondary PreventionCenters for Disease Control and Prevention (U.S.)Accident PreventionRisk FactorsUnited StatesHIV InfectionsHealth PromotionPreventive Health ServicesHealth EducationHealth Knowledge, Attitudes, PracticePreventive MedicineRisk Reduction BehaviorIncidenceProgram EvaluationRandomized Controlled Trials as TopicTreatment OutcomeRisk AssessmentPrevalenceChemopreventionWounds and InjuriesRisk-TakingSexual BehaviorQuestionnairesPregnancyNeoplasmsPublic HealthTime FactorsSexually Transmitted DiseasesInfectious Disease Transmission, VerticalCost-Benefit AnalysisCross-Sectional StudiesMass ScreeningPractice Guidelines as TopicFollow-Up StudiesAspirinProgram DevelopmentSchool Health ServicesHomosexuality, MaleRecurrenceProspective StudiesAnticarcinogenic AgentsPopulation SurveillanceCardiovascular DiseasesAccidental FallsInfant, NewbornDouble-Blind MethodCounselingClinical Trials as TopicTertiary PreventionLife StyleEvidence-Based MedicineCommunity Health ServicesCondomsSmoking