title: In vitro fertilization versus conversion to intrauterine insemination in the setting of three or fewer follicles: how should patients proceed when follicular response falls short of expectation?
abstract: OBJECTIVE
  To determine whether in vitro fertilization (IVF) cycles with suboptimal response should be converted to intrauterine insemination (IUI) or proceed to oocyte retrieval (OR).
  
  
  METHODS
  Retrospective cohort.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  All patients initiating IVF from January 2004 through December 2011.
  
  
  METHODS
  OR versus conversion to IUI.
  
  
  METHODS
  A total of 1,098 patients were identified whose IVF cycles were characterized by recruitment of three or fewer follicles, excluding patients with bilateral tubal disease or severe male factor. Cycles with three follicles were defined as those with three follicles ≥ 14 mm with no fourth follicle ≥ 10 mm. Cycles with two or fewer follicles were similarly defined. Outcomes were compared for patients proceeding with OR (n = 624) versus converting to IUI (n = 474). Age-adjusted relative risks for pregnancy were calculated, stratifying for number of follicles.
  
  
  RESULTS
  The likelihood of retrieving at least one mature oocyte (82.9% vs. 94.8% vs. 96.2%), having at least one zygote (61.9% vs. 76.8% vs. 84.2%), and undergoing transfer (57.1% vs. 73.0% vs. 83.3%) increased significantly with increasing follicle number. Patients with three or fewer follicles were 2.6 times more likely to achieve a live birth with IVF versus IUI (9.3% vs. 3.4%). This benefit was only apparent when at least two follicles were present. No benefit was gained by performing OR in the setting of one follicle.
  
  
  CONCLUSIONS
  IVF compared with IUI presents superior pregnancy rates in the setting of two or more follicles. Assisted reproduction programs may benefit their patients by pursuing IVF in this scenario.
authors.affiliation: Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medical Center, New York, New York 10021, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Reichman
authors.forename: Vinay
authors.initials: V
authors.lastname: Gunnala
authors.forename: Laura
authors.initials: L
authors.lastname: Meyer
authors.forename: Steven
authors.initials: S
authors.lastname: Spandorfer
authors.forename: Glenn
authors.initials: G
authors.lastname: Schattman
authors.forename: Owen K
authors.initials: OK
authors.lastname: Davis
authors.forename: Zev
authors.initials: Z
authors.lastname: Rosenwaks
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods* / Q000523:psychology / Q000639:trends; D006801:Humans; D007314:Insemination / Q000502:physiology*; D054315:Oocyte Retrieval / Q000379:methods* / Q000523:psychology / Q000639:trends; D006080:Ovarian Follicle / Q000502:physiology*; D011247:Pregnancy; D018873:Pregnancy Rate / Q000639:trends*; D012189:Retrospective Studies