title: Fertilization and in vitro development of cryopreserved human prophase I oocytes.
abstract: OBJECTIVE
  To determine the potential for in vitro maturation, fertilization, and cleavage after cryopreservation of immature, prophase I human oocytes.
  
  
  METHODS
  Immature oocytes obtained in excess of the number required by the patient were randomized and cryopreserved at the prophase I stage or cultured as control. After thawing and maturation in vitro, test and control oocytes were inseminated with husband's sperm and evaluated for fertilization and cleavage in vitro.
  
  
  METHODS
  In vitro fertilization program.
  
  
  METHODS
  Consenting patients undergoing controlled ovarian hyperstimulation for the purposes of IVF.
  
  
  METHODS
  Rates of maturation to metaphase II, fertilization, and cleavage were compared between control and cryopreserved oocytes.
  
  
  RESULTS
  Upon thaw, 58.5% (72/123) of prophase I oocytes were viable. Control oocytes demonstrated a 74.8% (98/131) maturation rate to metaphase II, a 56.5% (52/92) fertilization rate, and an 11.5% (6/52) blastocyst rate. Cryopreserved oocytes showed a 83.3% (60/72) rate of maturation, a 57.7% (30/52) fertilization rate, and a 3.3% (1/30) blastocyst rate. No significant differences were noted between any of these parameters.
  
  
  CONCLUSIONS
  These results demonstrate that prophase I oocytes from stimulated IVF cycles are able to survive cryopreservation and resume meiosis to achieve full nuclear maturation post-thaw. In addition, cryopreserved oocytes retain the same capacity for fertilization and development as control oocytes.
authors.affiliation: Jones Institute for Reproductive Medicine, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk 23507.
authors.forename: T L
authors.initials: TL
authors.lastname: Toth
authors.forename: S G
authors.initials: SG
authors.lastname: Baka
authors.forename: L L
authors.initials: LL
authors.lastname: Veeck
authors.forename: H W
authors.initials: HW
authors.lastname: Jones
authors.forename: S
authors.initials: S
authors.lastname: Muasher
authors.forename: S E
authors.initials: SE
authors.lastname: Lanzendorf
mesh_terms: D000328:Adult; D015925:Cryopreservation; D005260:Female; D005298:Fertility / Q000502:physiology; D005306:Fertilization / Q000502:physiology*; D005307:Fertilization in Vitro; D006801:Humans; D066298:In Vitro Techniques; D008677:Metaphase; D009865:Oocytes / Q000166:cytology / Q000502:physiology*; D010053:Ovary / Q000502:physiology; D010062:Ovulation Induction; D011418:Prophase; D014021:Tissue Preservation