title: Successful pregnancies and deliveries after a simple vitrification protocol for day 3 human embryos.
abstract: OBJECTIVE
  To evaluate the efficacy and efficiency of freezing cleaved human embryos through vitrification.
  
  
  METHODS
  Clinical study of vitrification of human embryos.
  
  
  METHODS
  Assisted reproductive technology centers.
  
  
  METHODS
  Thirty-six patients undergoing IVF-ICSI treatment whose surplus embryos were frozen.
  
  
  METHODS
  Two hundred fifteen surplus embryos vitrified, subsequently thawed, and transferred in natural or controlled cycles.
  
  
  METHODS
  Embryo survival rate after thawing and resultant patient pregnancy rate.
  
  
  RESULTS
  From the 215 vitrified and thawed embryos, 106 survived, with an overall embryo survival rate of 49.3%. The survival rate was higher when embryos were vitrified at the eight-cell stage compared with at the six to seven-cell and six-cell stages (79.2%, 39.7%, and 21.1%, respectively). On average, 2.9 +/- 1.2 embryos per patient were transferred, resulting in 11 pregnancies (30.5%), with an implantation rate of 10.4% per embryo transferred.
  
  
  CONCLUSIONS
  Ultrarapid embryo freezing by vitrification of eight-cell stage embryos is a reliable method, as evidenced by high rates of embryo survival and pregnancy, making it a superior alternative to the conventional slow-cooling method.
authors.affiliation: California Reproductive Laboratories, San Francisco, California 94109, USA. idanasouri@aol.com
authors.forename: I
authors.initials: I
authors.lastname: El-Danasouri
authors.forename: H
authors.initials: H
authors.lastname: Selman
mesh_terms: D000328:Adult; D001757:Blastomeres / Q000502:physiology; D015925:Cryopreservation / Q000379:methods*; D004622:Embryo, Mammalian; D005260:Female; D006801:Humans; D008297:Male; D011247:Pregnancy