Human immature oocytes grow during culture for IVM.

Background: Oocyte competence for maturation and embryogenesis is associated with diameter in many mammals. We aimed to test whether this relationship exists in humans and to quantify its impact upon in vitro maturation (IVM).

Methods: We used computer-assisted image analysis daily to measure average diameter, zona thickness and other parameters in oocytes.

The effects of meiosis activating sterol on in-vitro maturation and fertilization of human oocytes from stimulated and unstimulated ovaries.

The object of this study was to assess functional maturation in vitro by obtaining data on the fertilization and embryonic competence of human oocytes with or without exposure to meiosis activating sterol (MAS) during maturation in vitro. Immature oocytes were either collected from unstimulated patients with polycystic ovaries (PCO) during gynaecological surgery, or were donated by patients undergoing a cycle of intracytoplasmic sperm injection (ICSI) treatment including ovarian stimulation with gonadotrophins. PCO oocytes had variable cumulus cover, which was retained during culture while those from ICSI patients were cultured without cumulus.