title: The effects of smoking on ovarian function and fertility during assisted reproduction cycles.
abstract: OBJECTIVE
  To investigate the effects of cigarette smoking on ovarian function and fertility in women undergoing assisted reproduction cycles.
  
  
  METHODS
  We assessed the effects of smoking on ovarian function and fertility in a cohort of 499 women. Questionnaires were designed to quantify past smoking exposure and to determine whether the woman was smoking during the treatment cycle. Ovarian function characteristics and pregnancy rates were compared among current smokers, past smokers, and nonsmokers.
  
  
  RESULTS
  Compared with nonsmokers, both current and past smokers have reduced gonadotropin-stimulated ovarian function. A history of increasing tobacco exposure was associated with decreasing serum estradiol concentrations, numbers of retrieved oocytes, and numbers of embryos. On average, for every 10 pack-years of cigarette smoking, 2.5 fewer mature oocytes and 2.0 fewer embryos were obtained. Women who smoked during their treatment cycle had approximately a 50% reduction in implantation rate and ongoing pregnancy rate compared with women who had never smoked. Women who quit smoking before their treatment cycle had the same pregnancy rate as nonsmokers.
  
  
  CONCLUSIONS
  Cigarette smoking is associated with a prolonged and dose-dependent adverse effect on ovarian function. Smoking appears to have a more transient toxic effect on fertility, because current smokers, but not past smokers, had a markedly reduced pregnancy rate after treatment cycles compared with nonsmokers. Women should quit smoking before assisted reproduction cycles.
authors.affiliation: Department of Obstetrics and Gynecology, University of Iowa College of Medicine, Iowa City, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Van Voorhis
authors.forename: J D
authors.initials: JD
authors.lastname: Dawson
authors.forename: D W
authors.initials: DW
authors.lastname: Stovall
authors.forename: A E
authors.initials: AE
authors.lastname: Sparks
authors.forename: C H
authors.initials: CH
authors.lastname: Syrop
mesh_terms: D000328:Adult; D005260:Female; D005298:Fertility; D005307:Fertilization in Vitro; D015181:Gamete Intrafallopian Transfer; D006801:Humans; D010053:Ovary / Q000502:physiology*; D011247:Pregnancy; D018873:Pregnancy Rate; D012099:Reproductive Techniques; D012907:Smoking / Q000503:physiopathology*; D017388:Zygote Intrafallopian Transfer