title: Relationship of the human cumulus-free oocyte maturational profile with in vitro outcome parameters after intracytoplasmic sperm injection.
abstract: OBJECTIVE
  We investigated whether the human oocyte maturational profile at the removal of cumulus/corona cells affects the fertilization rate and subsequent embryo quality after intracytoplasmic sperm injection.
  
  
  METHODS
  A total of 1011 oocytes from 150 cycles was included in this retrospective analysis. Cumulus-free oocytes that were in prophase or metaphase I of meiosis at the removal of cumulus/corona cells were incubated in vitro until they reached metaphase II (in vitro-matured oocytes) and were then immediately injected with a single spermatozoa. Oocytes that were in metaphase II at the removal of cumulus/corona cells (MII oocytes) received sperm injection after 3-4 hr of preinjection incubation.
  
  
  RESULTS
  The fertilization rate of the MII oocytes was significantly higher than that of in vitro-matured oocytes (81 vs 62%; P < 0.001). The cleavage rates were similar in the two groups (MII oocytes, 94%; in vitro-matured oocytes, 91%). However, MII oocytes had significantly higher percentages of good-quality embryos (grade 1-3 embryos, 87 vs 58%, P < 0.001) and embryos with high cumulative embryo scores (score 10-32 embryos, 62 vs 33%, P < 0.001). The mean cumulative embryo score of MII oocytes after fertilization was also higher than that of in vitro-matured oocytes (12.1 +/- 3.8 vs 8.8 +/- 3.4; P = 0.014).
  
  
  CONCLUSIONS
  MII oocytes that extruded the first polar body at the removal of cumulus/corona cells had better fertilization rates and embryo morphology than in vitro-matured oocytes that extruded the first polar body following the removal of cumulus/corona cells and in vitro culture.
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Kaohsiung County, Taiwan, Republic of China.
authors.forename: F J
authors.initials: FJ
authors.lastname: Huang
authors.forename: S Y
authors.initials: SY
authors.lastname: Chang
authors.forename: M Y
authors.initials: MY
authors.lastname: Tsai
authors.forename: Y C
authors.initials: YC
authors.lastname: Lin
authors.forename: F T
authors.initials: FT
authors.lastname: Kung
authors.forename: J F
authors.initials: JF
authors.lastname: Wu
authors.forename: Y J
authors.initials: YJ
authors.lastname: Lu
mesh_terms: D004622:Embryo, Mammalian / Q000166:cytology; D005314:Embryonic and Fetal Development; D005260:Female; D006801:Humans; D008297:Male; D009865:Oocytes / Q000166:cytology*; D011247:Pregnancy; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods