title: Cryopreserved oocytes of infertile couples undergoing assisted reproductive technology could be an important source of oocyte donation: a clinical report of successful pregnancies.
abstract: BACKGROUND
  Surplus oocytes in assisted reproduction treatment cycles could be saved and donated to other couples. ICSI is usually performed for oocytes that have been stored frozen, considering possible exocytosis of cortical granules (CG). The unavoidability of ICSI merits further study.
  
  
  METHODS
  We used a slow method to freeze excess oocytes from infertile couples. After thawing, oocytes were fertilized by either IVF or ICSI according to semen parameters. Some oocytes were examined for CG.
  
  
  RESULTS
  Twenty-eight infertile couples cryopreserved a proportion of their oocytes and 12 thawed their oocytes. Three couples used their own oocytes, whereas nine donated their oocytes to nine other couples for 12 cycles. The survival rate from thawing was 90% (73/81). The fertilization rate using IVF (83%) was similar to ICSI (82%). Seven pregnancies (47% per cycle) were achieved; one used her own oocytes and six received donated oocytes. Five women delivered six babies including one set of twins. Two pregnancies aborted. The frozen-thawed oocytes (15/15) revealed no exocytosis of CG.
  
  
  CONCLUSIONS
  To freeze oocytes of infertile couples undergoing assisted reproduction treatment may help other couples. Our successful experience may facilitate oocyte banks to become a reality. Both IVF and ICSI are valuable for frozen oocytes.
authors.affiliation: Reproduction and Genetic Center, First Hospital of Peking University, Peking University, Beijing, China. l_xiaoh@yahoo.com.cn
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Li
authors.forename: Shee-Uan
authors.initials: SU
authors.lastname: Chen
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.forename: Miao
authors.initials: M
authors.lastname: Tang
authors.forename: Yuan-Rong
authors.initials: YR
authors.lastname: Kui
authors.forename: Xueqing
authors.initials: X
authors.lastname: Wu
authors.forename: Song
authors.initials: S
authors.lastname: Wang
authors.forename: Ying-Lu
authors.initials: YL
authors.lastname: Guo
mesh_terms: D000328:Adult; D019921:Biotinylation; D015925:Cryopreservation; D004624:Embryo Transfer; D005089:Exocytosis; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D016650:Fluorescein-5-isothiocyanate / Q000494:pharmacology; D005615:Freezing; D006801:Humans; D007150:Immunohistochemistry; D007246:Infertility; D037102:Lectins / Q000737:chemistry; D008297:Male; D018587:Oocyte Donation / Q000379:methods*; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism / Q000473:pathology; D010865:Pilot Projects; D011247:Pregnancy; D011256:Pregnancy Outcome; D027724:Reproductive Techniques, Assisted; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods; D013997:Time Factors
chemical_list: D037102:Lectins; D016650:Fluorescein-5-isothiocyanate