title: In vitro blastocyst formation of human oocytes obtained from unstimulated and stimulated cycles after vitrification at various maturational stages.
abstract: OBJECTIVE
  To evaluate the developmental competence and chromosomal normality of oocytes vitrified at various times after maturation culture.
  
  
  METHODS
  In vitro model study.
  
  
  METHODS
  A university-affiliated hospital.
  
  
  METHODS
  Unstimulated women who underwent cesarean section or oophorectomy and infertile women who underwent a long protocol of GnRH stimulation.
  
  
  METHODS
  Retrieved oocytes were vitrified at 0 or 48 hours after culture in unstimulated cycles and at 0, 8-15, or 24-28 hours after culture in stimulated cycles.
  
  
  METHODS
  Postthaw morphologic normality, maturation, fertilization, cleavage, blastocyst formation, and chromosome number.
  
  
  RESULTS
  In the 53 oocytes that were obtained from unstimulated cycles, no statistically significant differences were found in rates of morphologic normality (range, 56%-63%) or fertilization (range, 31%-37%) according to the time of vitrification. In the 50 oocytes that were obtained from stimulated cycles, more of those that were vitrified at 24-28 hours were morphologically normal than those that were vitrified at 0 or 8-15 hours. Regardless of these differences, high cleavage rates (83%-100%) were obtained that did not differ significantly among the treatment groups. In both cycles, 20%-43% of cleaved oocytes developed to the blastocyst stage by 6 days after IVF. All the karyotyped blastocysts, three from unstimulated cycles and four from stimulated cycles, had a normal number of chromosomes.
  
  
  CONCLUSIONS
  Vitrified and thawed oocytes from unstimulated or stimulated cycles developed to the blastocyst stage, regardless of when vitrification occurred; the number of chromosomes in the blastocysts was normal.
authors.affiliation: College of Medicine, Pochon CHA University, Infertility Medical Center of CHA General Hospital, Seoul, South Korea. artchung@netsgo.com
authors.forename: H M
authors.initials: HM
authors.lastname: Chung
authors.forename: S W
authors.initials: SW
authors.lastname: Hong
authors.forename: J M
authors.initials: JM
authors.lastname: Lim
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: W T
authors.initials: WT
authors.lastname: Cha
authors.forename: J J
authors.initials: JJ
authors.lastname: Ko
authors.forename: S Y
authors.initials: SY
authors.lastname: Han
authors.forename: D H
authors.initials: DH
authors.lastname: Choi
authors.forename: K Y
authors.initials: KY
authors.lastname: Cha
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000502:physiology*; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D015925:Cryopreservation / Q000379:methods*; D046508:Culture Techniques / Q000379:methods; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists / Q000494:pharmacology; D006801:Humans; D008297:Male; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D010062:Ovulation Induction; D012744:Sex Ratio; D020554:Sperm Injections, Intracytoplasmic
chemical_list: D007987:Gonadotropin-Releasing Hormone