title: Clinical factors associated with live birth after single embryo transfer.
abstract: OBJECTIVE
  To identify patient, cycle, and retrieval characteristics associated with embryo implantation and live birth in patients undergoing single embryo transfer (SET).
  
  
  METHODS
  Analysis of prospectively collected IVF database.
  
  
  METHODS
  Academic IVF program.
  
  
  METHODS
  All patient cycles meeting criteria for SET between June 2004 and September 2010.
  
  
  METHODS
  None.
  
  
  METHODS
  Clinical pregnancy and live birth.
  
  
  RESULTS
  Single embryo transfer was performed in 438 cycles, resulting in a clinical pregnancy rate of 76.2% and a live birth rate of 66.8% per transfer. Clinical pregnancy was associated with younger female age, ≥ 58% mature (metaphase II) oocytes at the time of retrieval, and increasing blastocyst expansion. Ongoing pregnancy was associated with younger female age and more advanced blastocysts. A diagnosis of uterine factor was negatively associated with live birth.
  
  
  CONCLUSIONS
  Even in a favorable prognosis population, younger female age is associated with clinical pregnancy and live birth. Although all patients underwent blastocyst transfer, expanded and hatching blastocysts were strongly associated with pregnancy and live birth. A diagnosis of uterine factor was the only infertility diagnosis found to affect live birth after SET. Obesity did not negatively affect SET outcome. These findings may assist physicians in determining the best candidates for SET.
authors.affiliation: Department of Obstetrics and Gynecology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA.
authors.forename: Jessica D K
authors.initials: JD
authors.lastname: Kresowik
authors.forename: Amy E T
authors.initials: AE
authors.lastname: Sparks
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Van Voorhis
mesh_terms: D000328:Adult; D000367:Age Factors; D001757:Blastomeres / Q000502:physiology*; D016009:Chi-Square Distribution; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects; D006801:Humans; D007247:Infertility, Female / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D007484:Iowa; D050498:Live Birth; D016015:Logistic Models; D015999:Multivariate Analysis; D016017:Odds Ratio; D054315:Oocyte Retrieval; D018579:Patient Selection; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D056826:Single Embryo Transfer / Q000009:adverse effects; D016896:Treatment Outcome; D055815:Young Adult