title: Cumulative pregnancy probabilities among couples with subfertility: effects of varying treatments.
abstract: OBJECTIVE
  To model the cumulative probability of pregnancy among couples with subfertility without a definitive diagnosis, according to different treatment strategies.
  
  
  METHODS
  A beta distribution of fecundity was fitted that reproduced the cumulative probability of pregnancy in prospective studies of natural fertility, and this distribution was applied to simulated cohorts starting with one million couples each. Probabilities of pregnancy were generated for each cycle of each couple.
  
  
  METHODS
  Simulation study.
  
  
  METHODS
  Hypothetic subfertile population.
  
  
  METHODS
  After 2 or 4 years of attempting pregnancy and diagnostic evaluation to exclude anovulation, tubal obstruction, and severe male factor, simulated treatments were applied to the remaining nonpregnant couples, with treatment effects based on published literature.
  
  
  METHODS
  Simulated cumulative probability of pregnancy.
  
  
  RESULTS
  Initially, the cumulative probability of pregnancy was highest for early treatment with IVF, but over time, conservative treatment or frequent intercourse approached the same cumulative probability.
  
  
  CONCLUSIONS
  In couples without clear indications for IVF, the main benefit of early IVF may be to shorten time to pregnancy, a benefit that must be weighed against costs and potential adverse outcomes. Couples should be encouraged to maintain regular intercourse to maximize chances of pregnancy, even after unsuccessful treatment attempts.
authors.affiliation: Department of Family and Preventive Medicine, Division of Public Health, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Stanford
authors.forename: Rafael T
authors.initials: RT
authors.lastname: Mikolajczyk
authors.forename: Courtney D
authors.initials: CD
authors.lastname: Lynch
authors.forename: Sara E
authors.initials: SE
authors.lastname: Simonsen