Longitudinal StudiesCohort StudiesBirth WeightCohort EffectInfant, NewbornPremature BirthPregnancyInfant, Low Birth WeightBirth RateRisk FactorsBirth OrderProspective StudiesBirth CertificatesPrenatal Exposure Delayed EffectsDenmarkAge FactorsChild DevelopmentBrazilGreat BritainMaternal AgeGestational AgeIncidenceMaternal ExposureSocioeconomic FactorsRespiratory SoundsMothersFinlandSex FactorsPrevalenceFollow-Up StudiesBreast FeedingBody HeightSocial ClassPregnancy OutcomeEducational StatusBody Mass IndexEczemaInfant MortalitySmokingTime FactorsLogistic Models