Birth OrderBirth WeightPaternal AgeMaternal AgeInfant, NewbornSiblingsBirth IntervalsBirth RateInfant, Low Birth WeightPregnancySex RatioPremature BirthFamily CharacteristicsParityAzerbaijanSibling RelationsGestational AgeRisk FactorsGravidityTwinsEczemaMothersDelivery, ObstetricInfant MortalityCase-Control StudiesBreast FeedingSocioeconomic FactorsOdds RatioBirth CertificatesGender IdentityHypersensitivity, ImmediateCohort StudiesPrenatal Exposure Delayed EffectsFetal DeathIntelligence TestsNorwayMaternal ExposureSocial ClassLogistic ModelsRhinitis, Allergic, SeasonalSwedenEducational Status