title: The effect of preincubation period of oocytes on nuclear maturity, fertilization rate, embryo quality, and pregnancy outcome in IVF and ICSI.
abstract: OBJECTIVE
  To clarify the effect of preincubation of oocytes on the results of IVF and ICSI.
  
  
  METHODS
  A total of 176 IVF and 64 ICSI cycles received long protocol ovarian stimulation. The oocytes were incubated for 1-8 h before insemination or sperm injection. Metaphase II (MII) percentage was evaluated in the ICSI arm; fertilization rates, embryo quality, and pregnancy outcomes were analyzed in both IVF and ICSI arms according to the preincubation period duration of oocytes.
  
  
  RESULTS
  The MII percentage of the ICSI arm was significantly lower (P < 0.05) in the group with preincubation period of < 2.5 h. The fertilization rates in groups with preincubation for 2.5-5.5 h were significantly higher (P < 0.001) for IVF. Embryo quality and pregnancy outcomes were not significantly different between the IVF or ICSI arm.
  
  
  CONCLUSIONS
  The preincubation of oocytes for at least 2.5 h is beneficial to both IVF and ICSI outcomes by increasing the nuclear maturity of oocytes.
authors.affiliation: Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, 160, Sec. 3, Chung-Kang Road, Taichung 407, Taiwan, Republic of China.
authors.forename: Jason Yen-Ping
authors.initials: JY
authors.lastname: Ho
authors.forename: Ming-Jer
authors.initials: MJ
authors.lastname: Chen
authors.forename: Yu-Chiao
authors.initials: YC
authors.lastname: Yi
authors.forename: Hwa-Fen
authors.initials: HF
authors.lastname: Guu
authors.forename: Esther Shih-Chu
authors.initials: ES
authors.lastname: Ho
mesh_terms: D004622:Embryo, Mammalian / Q000502:physiology; D005260:Female; D005306:Fertilization / Q000502:physiology*; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D008297:Male; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D013997:Time Factors