title: External validation of a prediction model for an ongoing pregnancy after intrauterine insemination.
abstract: OBJECTIVE
  To assess the accuracy of our recently developed prediction model in a prospective validation study to predict the outcome of intrauterine insemination (IUI).
  
  
  METHODS
  Descriptive prospective validation study.
  
  
  METHODS
  Seven fertility centers in the Netherlands.
  
  
  METHODS
  Couples treated with IUI of whom the female partner had a regular cycle.
  
  
  METHODS
  Intrauterine insemination with or without controlled ovarian hyperstimulation.
  
  
  METHODS
  Ongoing pregnancy after intrauterine insemination. Performance of the prediction model was assessed with calibration and discriminative capacity. Calibration was assessed by comparing the predicted ongoing pregnancy rate with the observed ongoing pregnancy rate. Discriminative capacity was assessed with receiver operation characteristic (ROC) analysis. For daily practice, a score worksheet of the validated model was developed to estimate the chance of an ongoing pregnancy after IUI per treatment cycle.
  
  
  RESULTS
  We included 1,079 subfertile couples who underwent 4,244 cycles of IUI. There were 278 ongoing pregnancies, that is, an ongoing pregnancy rate of 6.6% per cycle. External validation of the model showed good calibration. The predicted probability never differed by more than 1.5% of the mean observed probability. The area under the ROC curve was 0.56 (95% confidence interval, 0.53-0.59) at external validation.
  
  
  CONCLUSIONS
  The prediction model was able to make a good distinction between couples with a good pregnancy chance and those with a poor pregnancy chance after IUI. This model can help in deciding which couples will benefit from IUI and which couples will not.
authors.affiliation: Center for Reproductive Medicine, Academic Medical Center, Amsterdam, The Netherlands. i.m.custers@amc.uva.nl
authors.forename: Inge M
authors.initials: IM
authors.lastname: Custers
authors.forename: Pieternel
authors.initials: P
authors.lastname: Steures
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: van der Steeg
authors.forename: Thierry J H M
authors.initials: TJ
authors.lastname: van Dessel
authors.forename: Rob E
authors.initials: RE
authors.lastname: Bernardus
authors.forename: Petra
authors.initials: P
authors.lastname: Bourdrez
authors.forename: Carolien A M
authors.initials: CA
authors.lastname: Koks
authors.forename: Wernard J
authors.initials: WJ
authors.lastname: Riedijk
authors.forename: Jan M
authors.initials: JM
authors.lastname: Burggraaff
authors.forename: Fulco
authors.initials: F
authors.lastname: van der Veen
authors.forename: Ben W J
authors.initials: BW
authors.lastname: Mol
mesh_terms: D000328:Adult; D002138:Calibration; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007246:Infertility / Q000175:diagnosis* / Q000628:therapy*; D007315:Insemination, Artificial; D008297:Male; D015233:Models, Statistical; D011247:Pregnancy; D018873:Pregnancy Rate; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome