title: Five-years of a mandatory single-embryo transfer (mSET) policy dramatically reduces twinning rate without lowering pregnancy rates.
abstract: OBJECTIVE
  To report the outcomes of a program policy instituted in 2004 mandating single-embryo transfer (mSET) for all women aged <38 years, with at least seven zygotes, no prior failed fresh cycle at our center, and at least one good-quality blastocyst.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  All women <38 years old undergoing a fresh cycle with autologous oocytes and all women undergoing a fresh cycle with donor oocytes from June 1, 1999, to May 31, 2004 (before mSET) and from June 1, 2004, to May 31, 2009 (after mSET).
  
  
  METHODS
  mSET policy implementation.
  
  
  METHODS
  Live-birth rate, multiple pregnancy rate, clinical volume, and outcomes of all mSET fresh IVF transfers were analyzed.
  
  
  RESULTS
  Clinical volume was unchanged between the two time groups. After implementation of mSET, live-birth rates improved from 51.1% to 55.9% and multiple-birth rates dropped from 34.8% to 17.5%. A total of 364 mSET fresh transfers were performed with a live-birth rate of 64.6% and a multiple-birth rate of 3.4%.
  
  
  CONCLUSIONS
  A mandatory SET policy based on prognostic factors can be instituted with no drop in clinical volume and no negative effect on delivery rates. Multiple gestation rates can be dramatically lowered.
authors.affiliation: Department of Obstetrics and Gynecology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
authors.forename: Jessica D
authors.initials: JD
authors.lastname: Kresowik
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Stegmann
authors.forename: Amy E
authors.initials: AE
authors.lastname: Sparks
authors.forename: Ginny L
authors.initials: GL
authors.lastname: Ryan
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: van Voorhis
mesh_terms: D000328:Adult; D015536:Down-Regulation; D005260:Female; D005307:Fertilization in Vitro / Q000331:legislation & jurisprudence*; D019983:Guideline Adherence; D006284:Health Plan Implementation; D006801:Humans; D037141:Mandatory Programs / Q000331:legislation & jurisprudence; D011247:Pregnancy; D018873:Pregnancy Rate / Q000639:trends*; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data*; D056826:Single Embryo Transfer / Q000706:statistics & numerical data*; D013997:Time Factors; D014427:Twins / Q000706:statistics & numerical data*