title: [Smoking is associated with increased risk of ectopic pregnancy--a population based study].
abstract: BACKGROUND
  There has been a world-wide increase in the incidence of ectopic pregnancies over the last decades. In Norway about 1,500 women are hospitalized every year because of this potentially lethal condition. Several studies have shown that smoking is one of several risk factors for ectopic pregnancies. We wanted to examine whether such an association could be established in a large Norwegian material.
  
  
  METHODS
  We analysed data from a cross-sectional questionnaire-based study of 9,237 Norwegian women aged 35-49 years. 61.6% responded.
  
  
  RESULTS
  67.4% of the women were present or previous smokers. 301 (3.3%) had experienced an ectopic pregnancy. We found that smokers had a relative risk of 1.5 (95% CI 1.1-1.9) for ectopic pregnancy compared to non-smokers.
  
  
  CONCLUSIONS
  Our results support other studies. Identification of risk factors is important in the prevention of ectopic pregnancies. Smoking is a risk factor for ectopic pregnancy that can be reduced through counselling.
authors.affiliation: Institutt for samfunnsmedisin Universitetet i Tromsø 9037 Tromsø.
authors.forename: Lena
authors.initials: L
authors.lastname: Aronsen
authors.forename: Maja-Lisa
authors.initials: ML
authors.lastname: Løchen
authors.forename: Eiliv
authors.initials: E
authors.lastname: Lund
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D011795:Surveys and Questionnaires
vernacular_title: Røyking er assosiert med økt risiko for ekstrauterine svangerskap.