title: Validation of a model predicting spontaneous pregnancy among subfertile untreated couples.
abstract: OBJECTIVE
  To provide external validation of the Eimers model, which predicts spontaneous pregnancy among subfertile couples within the first year after the definitive establishment of the diagnostic category.
  
  
  METHODS
  Live birth rates predicted by an adapted version of the Eimers model were tested against observed live birth rates in a Canadian cohort study.
  
  
  METHODS
  Fertility clinics in university medical centers.
  
  
  METHODS
  One thousand sixty-one couples consulting for subfertility due to cervical hostility, male subfertility, or unexplained subfertility.
  
  
  METHODS
  None.
  
  
  METHODS
  We measured the discriminative ability and reliability of the predictions from the model.
  
  
  RESULTS
  The live birth rate was lower in the Canadian population than in the Eimers population. Overall, the prognostic effect of the predictors did not differ significantly in both populations. The model showed moderate predictive power in the Canadian population. With adjustment of the average live birth rate, the reliability of the model was satisfactory.
  
  
  CONCLUSIONS
  The Eimers model gave reliable spontaneous pregnancy predictions in the Canadian validation population after adjustment of the average live birth rate.
authors.affiliation: Center for Clinical Decision Sciences, Department of Public Health, Erasmus University Medical Center Rotterdam, The Netherlands. hunault@mgz.fgg.eur.nl
authors.forename: Claudine C
authors.initials: CC
authors.lastname: Hunault
authors.forename: Marinus J C
authors.initials: MJ
authors.lastname: Eijkemans
authors.forename: Egbert R
authors.initials: ER
authors.lastname: te Velde
authors.forename: John A
authors.initials: JA
authors.lastname: Collins
authors.forename: J Dik F
authors.initials: JD
authors.lastname: Habbema
mesh_terms: D000328:Adult; D000367:Age Factors; D001723:Birth Rate; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008954:Models, Biological; D011247:Pregnancy; D015203:Reproducibility of Results; D013081:Sperm Motility / Q000502:physiology*