title: Survival rate of human oocytes and pregnancy outcome after vitrification using slush nitrogen in assisted reproductive technologies.
abstract: OBJECTIVE
  To report the survival rate of oocytes and the rate of successful pregnancies obtained from super-rapid cooling of oocytes using slush nitrogen (SN(2)).
  
  
  METHODS
  Prospective clinical research.
  
  
  METHODS
  A university-affiliated hospital.
  
  
  METHODS
  Twenty-eight infertile women who underwent 30 cycles of IVF-ET using previously vitrified oocytes.
  
  
  METHODS
  Oocytes were vitrified by super-rapid cooling using SN(2).
  
  
  METHODS
  Morphological normality of thawed oocytes and clinical outcome.
  
  
  RESULTS
  In 30 cycles of ovarian stimulation for IVF, 364 surplus oocytes from 28 patients were vitrified using SN(2). Three hundred two (85.1% +/- 2.9%) of the oocytes survived after warming. Fertilization and cleavage rates were 77.4% +/- 3.5% (168/218) and 94.3% +/- 2.1% (158/168), respectively. Thirteen pregnancies (43.3%) resulted from 30 uterine transfers of 120 embryos with an implantation rate of 14.2% (17/120). There were no differences between the pregnancy rate after vitrification/warming and that obtained from routine noncryopreserved oocytes.
  
  
  CONCLUSIONS
  The present report suggests that super-rapid cooling may improve the clinical efficacy of human oocyte vitrification and may be a valuable tool for human assisted reproductive technologies.
authors.affiliation: Fertility Center of CHA General Hospital, CHA Research Institute, Pochon CHA University, College of Medicine, Seoul, Korea. tkyoon@cha.ac.kr
authors.forename: Tae Ki
authors.initials: TK
authors.lastname: Yoon
authors.forename: Dong Ryul
authors.initials: DR
authors.lastname: Lee
authors.forename: Soo Kyung
authors.initials: SK
authors.lastname: Cha
authors.forename: Hyung Min
authors.initials: HM
authors.lastname: Chung
authors.forename: Woo Sik
authors.initials: WS
authors.lastname: Lee
authors.forename: Kwang Yul
authors.initials: KY
authors.lastname: Cha
mesh_terms: D000328:Adult; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D009584:Nitrogen; D009865:Oocytes; D011247:Pregnancy; D011256:Pregnancy Outcome; D027724:Reproductive Techniques, Assisted
chemical_list: D009584:Nitrogen