The effect of preincubation period of oocytes on nuclear maturity, fertilization rate, embryo quality, and pregnancy outcome in IVF and ICSI

J Assist Reprod Genet. 2003 Sep;20(9):358-64. doi: 10.1023/a:1025476910771.


Purpose: 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.

MeSH terms

  • Embryo, Mammalian / physiology
  • Female
  • Fertilization / physiology*
  • Fertilization in Vitro / methods*
  • Humans
  • Male
  • Oocytes / physiology*
  • Pregnancy
  • Pregnancy Outcome*
  • Pregnancy Rate*
  • Retrospective Studies
  • Sperm Injections, Intracytoplasmic*
  • Time Factors