title: Association between perfluorinated compounds and time to pregnancy in a prospective cohort of Danish couples attempting to conceive.
abstract: BACKGROUND
  Perfluorinated chemicals (PFCs) have been widely used and have emerged as important food contaminants. A recent study on pregnant women suggested that PFC exposure was associated with a longer time to pregnancy (TTP). We examined the association between serum concentrations of PFCs in females and TTP in 222 Danish first-time pregnancy planners during the years 1992-1995.
  
  
  METHODS
  The couples were enrolled in the study when discontinuing birth control and followed for six menstrual cycles or until a clinically recognized pregnancy occurred. Fecundability ratio (FR) was calculated using discrete-time survival models. In addition, odds ratio (OR) for TTP >6 cycles was calculated.
  
  
  RESULTS
  OR for TTP >6 cycles for those with PFC concentrations above the median were 0.96 [95% confidence interval (CI): 0.54-1.64] for perfluorooctane sulfonic acid (PFOS), the major PFC, compared with those below the median. FRs for those with PFOS concentrations above the median were 1.05 (95% CI: 0.74-1.48) compared with those below the median. Other PFCs showed the same lack of association with TTP. The results were not affected by adjustment for covariates. PFOS and perfluorooctanoic acid concentrations were similar to those observed in a previous Danish study.
  
  
  CONCLUSIONS
  These findings suggest that exposure to PFCs affects TTP only to a small extent, if at all.
authors.affiliation: Department of Environmental Medicine, Institute of Public Health, University of Southern Denmark, J.B. Winsloews Vej 17A, DK-5000 Odense C, Denmark. svestergaard@health.sdu.dk
authors.forename: Sonja
authors.initials: S
authors.lastname: Vestergaard
authors.forename: Flemming
authors.initials: F
authors.lastname: Nielsen
authors.forename: Anne-Maria
authors.initials: AM
authors.lastname: Andersson
authors.forename: Niels Henrik
authors.initials: NH
authors.lastname: Hjøllund
authors.forename: Philippe
authors.initials: P
authors.lastname: Grandjean
authors.forename: Helle Raun
authors.initials: HR
authors.lastname: Andersen
authors.forename: Tina Kold
authors.initials: TK
authors.lastname: Jensen
mesh_terms: D000328:Adult; D017738:Alkanesulfonic Acids / Q000097:blood / Q000494:pharmacology*; D015331:Cohort Studies; D003718:Denmark; D005260:Female; D005298:Fertility / Q000187:drug effects*; D005466:Fluorocarbons / Q000097:blood / Q000494:pharmacology*; D005506:Food Contamination; D006801:Humans; D008297:Male; D018811:Maternal Exposure; D016017:Odds Ratio; D011247:Pregnancy; D013997:Time Factors
chemical_list: D017738:Alkanesulfonic Acids; D005466:Fluorocarbons; C076994:perfluorooctane sulfonic acid