title: Assisted reproductive technology practice patterns and the impact of embryo transfer guidelines in the United States.
abstract: OBJECTIVE
  [1] To evaluate trends in number of embryos transferred and resultant high-order multiple (HOM) pregnancy rates by Society for Assisted Reproductive Technology (SART)-member clinics between 1996 and 2003 and [2] to relate these practice patterns and outcomes to clinic compliance with SART-American Society for Reproductive Medicine (ASRM) embryo transfer guidelines.
  
  
  METHODS
  Retrospective.
  
  
  METHODS
  Society for Assisted Reproductive Technology-member fertility centers in the United States.
  
  
  METHODS
  Five hundred thirty-six thousand, five hundred twenty-four fresh, nondonor IVF cycles.
  
  
  METHODS
  None.
  
  
  METHODS
  Number of embryos transferred; pregnancy rates; implantation rates; and proportion of singleton, twin, and HOM pregnancies.
  
  
  RESULTS
  The number of embryos transferred declined each year. High-order multiple pregnancy rates also declined, whereas the twin rates remained stable. The most pronounced declines in number transferred occurred immediately after publication of SART-ASRM embryo transfer guidelines. After stratifying clinics according to mean and modal number of embryos transferred, clinics transferring the fewest embryos in women <35 years of age had the highest mean implantation and pregnancy rates. Furthermore, the percentage of clinics transferring two embryos to a majority of women <35 years of age increased from 3.3% in 1996 to 49.9% in 2003.
  
  
  CONCLUSIONS
  The implementation of SART-ASRM embryo transfer guidelines is associated with significant reductions in the number of embryos being transferred, along with reductions of HOM pregnancies. Initiatives to further reduce twin pregnancies and encourage singleton gestation outcomes are outlined.
authors: Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA. judy.stern@dartmouth.edu
authors: Judy E
authors: JE
authors: Stern
authors: Marcelle I
authors: MI
authors: Cedars
authors: Tarun
authors: T
authors: Jain
authors: Nancy A
authors: NA
authors: Klein
authors: C Martin
authors: CM
authors: Beaird
authors: David A
authors: DA
authors: Grainger
authors: William E
authors: WE
authors: Gibbons
mesh_terms: D000328:Adult; D002452:Cell Count; D004624:Embryo Transfer / Q000639:trends*; D005260:Female; D019983:Guideline Adherence; D006801:Humans; D008423:Maternal Age; D017410:Practice Guidelines as Topic; D010818:Practice Patterns, Physicians' / Q000639:trends*; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple; D027724:Reproductive Techniques, Assisted / Q000639:trends*; D012189:Retrospective Studies; D014481:United States