title: Removal of lysed blastomeres from frozen-thawed embryos improves implantation and pregnancy rates in frozen embryo transfer cycles.
abstract: OBJECTIVE
  To evaluate the effect of degenerated (lysed) blastomere removal on implantation and pregnancy rates in cleavage-stage cryo-embryo transfer (ET) cycles.
  
  
  METHODS
  Randomized clinical trial.
  
  
  METHODS
  Private reproductive medical center.
  
  
  METHODS
  A total of 88 patients who received frozen-thawed ET, divided into two groups.
  
  
  METHODS
  Embryo freezing and thawing; opening of the zona pellucida and removal of cryodamaged blastomeres (in the study group), followed by same-day ET.
  
  
  METHODS
  Extent of survival of cleavage-stage embryos after the freeze-thaw procedure; embryo implantation and clinical pregnancies.
  
  
  RESULTS
  Oocyte number per patient, fertilization rate, embryo development rate (and quality), and freezing rates were similar in the two groups in the fresh cycle. In the control group, a total of 55 embryos (25%) of the 217 thawed remained fully intact, and 53 (26%) of the 207 in the study group remained intact. The average number of embryos transferred per group was similar (control, 3.4 +/- 0.9; study, 3.3 +/- 0.9). Implantation rates were 12% and 26% in the control and study groups, respectively. The clinical pregnancy rate was 23% in the control group and 64% in the study group when lysed cell removal was performed.
  
  
  CONCLUSIONS
  The results show that pregnancy and implantation rates are higher in the study group; therefore, the removal of degenerated blastomeres may be beneficial to all patients who undergo cleavage-stage, frozen-thawed ET.
authors.affiliation: Reproductive Biology Associates, Atlanta, Georgia 30342, USA. nagy.zsolt.peter@iol.it
authors.forename: Zsolt P
authors.initials: ZP
authors.lastname: Nagy
authors.forename: Tyl
authors.initials: T
authors.lastname: Taylor
authors.forename: Thomas
authors.initials: T
authors.lastname: Elliott
authors.forename: Joe B
authors.initials: JB
authors.lastname: Massey
authors.forename: Hilton I
authors.initials: HI
authors.lastname: Kort
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Shapiro
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000166:cytology*; D001757:Blastomeres / Q000473:pathology*; D002469:Cell Separation / Q000379:methods; D002470:Cell Survival; D015925:Cryopreservation; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D009865:Oocytes / Q000166:cytology; D011247:Pregnancy; D018873:Pregnancy Rate