title: Single blastocyst transfer: a prospective randomized trial.
abstract: OBJECTIVE
  To determine the efficacy of single blastocyst transfer.
  
  
  METHODS
  Prospective randomized trial.
  
  
  METHODS
  Private assisted reproductive technology unit.
  
  
  METHODS
  Forty-eight women undergoing IVF-embryo transfer with day 3 FSH <or=10 mIU/mL and at least 10 follicles >12 mm in diameter on day of hCG administration.
  
  
  METHODS
  Embryo culture to the blastocyst stage in sequential media G1/G2 followed by transfer of either one or two blastocysts.
  
  
  METHODS
  Implantation rate, ongoing pregnancy rate, and twinning.
  
  
  RESULTS
  The transfer of a single blastocyst resulted in an implantation and ongoing pregnancy rate of 60.9% with no twins. The transfer of two blastocysts resulted in an implantation rate of 56%, an ongoing pregnancy rate of 76% with a 47.4% incidence of twins.
  
  
  CONCLUSIONS
  Single blastocyst transfer is an effective method of eliminating multiple births while maintaining high pregnancy rates in this selected group of patients.
authors.affiliation: Colorado Center for Reproductive Medicine, Englewood, Colorado 80110, USA. dgardner@colocrm.com
authors.forename: David K
authors.initials: DK
authors.lastname: Gardner
authors.forename: Eric
authors.initials: E
authors.lastname: Surrey
authors.forename: Debra
authors.initials: D
authors.lastname: Minjarez
authors.forename: Annette
authors.initials: A
authors.lastname: Leitz
authors.forename: John
authors.initials: J
authors.lastname: Stevens
authors.forename: William B
authors.initials: WB
authors.lastname: Schoolcraft
mesh_terms: D000328:Adult; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data; D016896:Treatment Outcome; D014427:Twins / Q000706:statistics & numerical data