title: The maturity of human cumulus-free oocytes is positively related to blastocyst development and viability.
abstract: OBJECTIVE
  We investigated whether the human oocyte maturity at the removal of cumulus/corona cells affects the embryo outcome in vitro.
  
  
  METHODS
  A total of 620 oocytes, which subsequently underwent blastocyst culture, were included in this analysis. Oocytes that were in prophase or Metaphase I of meiosis at the removal of cumulus/corona cells were in Group II. Oocytes that were in Metaphase II at the removal of cumulus/corona cells were in Group I.
  
  
  RESULTS
  Group I oocytes yielded the highest fertilization rates (96.3% vs. 77.1%, P < 0.001). The incidence of Group II oocytes developing to the blastocyst stage was significantly less than from Group I oocytes (38.1% vs. 86.1%, P < 0.001). The percentage of top-scoring blastocysts from Group I oocytes was higher than that of Group II oocytes (95.4% vs. 76.2%, P < 0.001).
  
  
  CONCLUSIONS
  Oocyte maturity at the removal of cumulus/corona cells needs to be considered in selecting good quality blastocysts for embryo transfer.
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Kaohsiung, Taiwan. huangfj@seed.net.tw
authors.forename: Fu-Jen
authors.initials: FJ
authors.lastname: Huang
authors.forename: Hsuan-Wei
authors.initials: HW
authors.lastname: Huang
authors.forename: Kuo-Chung
authors.initials: KC
authors.lastname: Lan
authors.forename: Fu-Tsai
authors.initials: FT
authors.lastname: Kung
authors.forename: Yi-Chi
authors.initials: YC
authors.lastname: Lin
authors.forename: Hsueh-Wen
authors.initials: HW
authors.lastname: Chang
authors.forename: Shiuh-Young
authors.initials: SY
authors.lastname: Chang
mesh_terms: D000328:Adult; D001755:Blastocyst / Q000166:cytology / Q000502:physiology*; D018929:Cell Culture Techniques / Q000379:methods; D002470:Cell Survival; D005260:Female; D006801:Humans; D008423:Maternal Age; D008540:Meiosis / Q000502:physiology; D008677:Metaphase / Q000502:physiology; D009865:Oocytes / Q000166:cytology* / Q000502:physiology*; D020554:Sperm Injections, Intracytoplasmic