title: Predictive value of 72-hour blastomere cell number on blastocyst development and success of subsequent transfer based on the degree of blastocyst development.
abstract: OBJECTIVE
  To determine the predictive value of 72-hour blastomere cell number on blastocyst development and to compare success rates of subsequent transfer based on the degree of blastocyst development.
  
  
  METHODS
  Retrospective clinical study.
  
  
  METHODS
  Private assisted reproductive technology center.
  
  
  METHODS
  Ninety-three women aged 32.0 +/- 5.1 years undergoing oocyte retrieval for IVF.
  
  
  METHODS
  Bipronucleate oocytes obtained from IVF were grown for up to 168 hours after fertilization and subsequently transferred at the blastocyst stage.
  
  
  METHODS
  Percentages of embryos developing to blastocyst from 72-hour embryos by blastomere cell number and subsequent implantation and pregnancy rates of transferred blastocysts.
  
  
  RESULTS
  Rates of blastocyst formation and expansion increased as cell numbers at 72 hours increased. Implantation rates were 43% for embryos transferred to women receiving only expanded blastocysts and 17% for embryos transferred to women receiving one or more less developed blastocysts. Pregnancy rates were higher for women receiving only expanded blastocysts than for women receiving one or more less developed blastocysts, although the difference was not significant.
  
  
  CONCLUSIONS
  More developed 72-hour embryos are more likely to become blastocysts and expand. Implantation rates are greater for the transfer of expanded rather than unexpanded blastocysts.
authors.affiliation: Fertility Center of Las Vegas, Las Vegas, Nevada 89117, USA. bsshapiro@aol.com
authors.forename: B S
authors.initials: BS
authors.lastname: Shapiro
authors.forename: D C
authors.initials: DC
authors.lastname: Harris
authors.forename: K S
authors.initials: KS
authors.lastname: Richter
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000166:cytology*; D001757:Blastomeres / Q000166:cytology*; D002452:Cell Count; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D013997:Time Factors