title: Human oocyte cryopreservation as an adjunct to IVF-embryo transfer cycles.
abstract: BACKGROUND
  The purpose of this work was to develop methods for successful cryopreservation of human oocytes.
  
  
  METHODS
  Two cryopreservation procedures were used. Method 1 involved use of 1.5 mol/l propanediol (PrOH)-0.1 mol/l sucrose with medium containing sodium (Na) as cryoprotectant medium, seeding at -7 degrees C, and stepwise dilution of cryoprotectant post-thaw. Method 2 used Na-depleted media with 1.5 mol/l PrOH-0.2 mol/l sucrose for freezing, seeding at -6 degrees C, and use of high sucrose (0.5 and 0.2 mol/l) for cryoprotectant removal.
  
  
  RESULTS
  The first method was used in seven patients, and gave poor (12.3%) survival results and no pregnancies. The second method was used in 15 patients (16 cycles), and yielded good survival and fertilization rates (74.4 and 59% respectively), with four pregnancies and five healthy infants born to 11 women receiving an embryo transfer.
  
  
  CONCLUSIONS
  Using Na-depleted media along with other alterations in freezing and thawing procedures, human oocyte cryopreservation can provide excellent survival and pregnancy rates.
authors.affiliation: Assisted Fertility Services, Community Health Network, Indianapolis, IN 46256, USA. jboldt@ecommunity.com
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Boldt
authors.forename: Donald
authors.initials: D
authors.lastname: Cline
authors.forename: David
authors.initials: D
authors.lastname: McLaughlin
mesh_terms: D002470:Cell Survival; D015925:Cryopreservation; D003451:Cryoprotective Agents; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D009865:Oocytes / Q000502:physiology*; D019946:Propylene Glycol; D012964:Sodium; D020554:Sperm Injections, Intracytoplasmic; D013395:Sucrose
chemical_list: D003451:Cryoprotective Agents; D013395:Sucrose; D019946:Propylene Glycol; D012964:Sodium