Objective: To evaluate whether germinal vesicle (GV) oocytes from stimulated cycles can be a source of embryos.
Design: In vitro model study.
Setting: Specialized laboratory of women's clinic.
Patient(s): Women in whom oocytes were retrieved at the GV stage.
Intervention(s): After culture of GV oocytes in the modified TLP medium with human follicular fluid, oocytes that reached the metaphase II stage underwent ICSI. Potential of fertilization and subsequent cleavage of in vitro-matured oocytes was compared with that of an in vivo-matured control.
Main outcome measure(s): Maturation rate, rate of pronuclei formation, and developmental activity.
Result(s): The maturation rate of GV oocytes from follicles primed with gonadotropin was not affected by the presence or absence of cumulus. However, the maturation was more synchronous in oocytes with cumulus than in those without cumulus. Proportions of oocytes with two pronuclei and embryos cleaved to the 16-cell stage after ICSI were significantly lower in the oocytes matured in vitro than in the oocytes matured in vivo.
Conclusion(s): Human GV oocytes from stimulated ovaries can be matured, fertilized, and developed in vitro. Production of embryos from GV oocytes will increase the opportunity for achieving pregnancy.