Pregnancy in AdolescenceBirth RateSibling RelationsPregnancyUnited StatesBirth WeightPremature BirthInfant, Low Birth WeightInfant, NewbornAbortion, InducedMaternal AgeBirth OrderBirth CertificatesSex EducationContraception BehaviorAdolescent BehaviorPregnancy OutcomeIllegitimacyPregnancy, UnwantedAbortion, LegalMothersAdolescent Health ServicesLicensureSocioeconomic FactorsFamily Planning ServicesSexual BehaviorGestational AgeInfant MortalityBirth IntervalsMethandrostenoloneAutomobile DrivingRisk FactorsAge FactorsCohort StudiesBirth InjuriesCoitusFetal DeathPregnancy ComplicationsCesarean SectionAdolescent PsychologyMultiple Birth OffspringPrenatal CareParityLongitudinal StudiesObstetric Labor, PrematureEducational StatusCongenital AbnormalitiesVital StatisticsFamily CharacteristicsEngland