title: Vacuum-assisted delivery is associated with late-onset asthma.
abstract: BACKGROUND
  Perinatal factors during delivery might modulate fetal immunological development and thereby be associated with the development of allergic diseases and asthma later.
  
  
  METHODS
  Perinatal data was recorded during pregnancy and at the time of delivery in regard to 5823 children who were born in Northern Finland in 1985-1986. Data from self-administered questionnaires were available at the ages of 7 and 15-16 years and skin prick tests for four main allergens were carried out at the age of 15-16 years. Only singletons delivered by the vaginal route were analyzed.
  
  
  RESULTS
  There was a higher prevalence of doctor-diagnosed asthma at any time of life among children who were delivered by vacuum extraction (RR 1.80, 95% CI 1.27-2.56; P < 0.001) in comparison with spontaneously delivered children. In particular, this risk was increased as regards late-onset asthma (RR 2.41, 95% CI 1.52-3.81; P < 0.001). Perinatal effects had less impact on the development of other asthma, atopy or hay fever.
  
  
  CONCLUSIONS
  The delivery by vacuum extraction had significant impact on the development of late-onset asthma compared with spontaneously delivered children.
authors.affiliation: Environmental Health Department, National Institute for Health and Welfare, Kuopio, Finland.|Department of Obstetrics and Gynecology, Kuopio University Hospital, Kuopio, Finland.
authors.forename: L
authors.initials: L
authors.lastname: Keski-Nisula
authors.affiliation: Department of Obstetrics and Gynecology, Kuopio University Hospital, Kuopio, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Harju
authors.affiliation: Department of Epidemiology and Public Health, Imperial College, London, UK.|Department of Public Health and General Practise, University of Oulu, Oulu, Finland.
authors.forename: M-R
authors.initials: MR
authors.lastname: Järvelin
authors.affiliation: Environmental Health Department, National Institute for Health and Welfare, Kuopio, Finland.|School of Clinical Nutrition and Public Health, University of Kuopio, Kuopio, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Pekkanen
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D000485:Allergens / Q000276:immunology; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology* / Q000276:immunology; D002648:Child; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000009:adverse effects; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology / Q000209:etiology / Q000276:immunology; D011247:Pregnancy; D015995:Prevalence; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology / Q000209:etiology / Q000276:immunology; D012882:Skin Tests; D014620:Vacuum Extraction, Obstetrical / Q000009:adverse effects*
chemical_list: D000485:Allergens