title: Delayed conception and active and passive smoking. The Avon Longitudinal Study of Pregnancy and Childhood Study Team.
abstract: OBJECTIVE
  To determine whether passive as well as active smoking by women or smoking by men is associated with delayed conception, after adjustment for confounding factors.
  
  
  METHODS
  Population study of couples expecting a baby. Logistic regression was performed to identify factors associated with delayed conception.
  
  
  METHODS
  The Avon Health Authority area, United Kingdom.
  
  
  METHODS
  All couples expected to deliver between April 1991 and December 1992.
  
  
  METHODS
  Questionnaires administered early in pregnancy.
  
  
  METHODS
  Time taken to conceive, categorized as <6 months, 6-11 months, 1-3 years, and >3 years.
  
  
  RESULTS
  After correction for confounding factors, delayed conception was statistically significantly associated with both active smoking by the woman (odds ratio [OR] 1.23 [95% CI 0.98-1.49] for > 6 months and 1.54 [95% CI 1.19-2.01] for >12 months) and her exposure to passive smoking (OR 1.17 [95% CI 1.02-1.37] and 1.14 [95% CI 0.92-1.42]) compared with women with no exposure to tobacco smoke (referent). Heavy smoking by men was independently associated with delayed conception. In active smokers, the effect increased with the number of cigarettes.
  
  
  CONCLUSIONS
  Smoking by men and passive and active smoking by women are associated with delayed conception.
authors.affiliation: Division of Obstetrics and Gynaecology, University of Bristol, Bristol, United Kingdom.
authors.forename: M G
authors.initials: MG
authors.lastname: Hull
authors.forename: K
authors.initials: K
authors.lastname: North
authors.forename: H
authors.initials: H
authors.lastname: Taylor
authors.forename: A
authors.initials: A
authors.lastname: Farrow
authors.forename: W C
authors.initials: WC
authors.lastname: Ford
mesh_terms: D000328:Adult; D001835:Body Weight; D005260:Female; D005306:Fertilization; D005865:Gestational Age; D006801:Humans; D007246:Infertility / Q000209:etiology*; D008137:Longitudinal Studies; D008297:Male; D011247:Pregnancy; D012907:Smoking / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D013997:Time Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D014028:Tobacco Smoke Pollution