RESUMEN
OBJECTIVE: The optimal culture conditions for human immature oocytes are still investigating. We compared retrospectively the efficacy of two culture media (pyruvate-dominant YS media vs glucose-dominant G2 media) on in vitro maturation and fertilization rate of immature oocytes obtained from stimulated IVF cycles. METHODS: One hundred forty-three immature oocytes (including GV and metaphase I) were obtained from 67 cycles of IVF-ET (52 patients). The mean age of female was 32.5+/-3.7 years. Ovarian hyperstimulation was performed using hMG or rFSH with GnRH antagonist and then ovulation was triggered by urinary or rhCG. Immature oocytes were cultured for 4-24 hrs and then fertilized by ICSI. We used YS media between July 2003 and September 2004, and G2 media between October 2004 and August 2005. Each media was prepared containing 30% of patients' follicular fluid, rFSH (1 IU/mL), rLH (1 IU/mL) and rEGF (10 ng/mL). RESULTS: The in vitro maturation rate of immature oocytes (67% vs 66%) and their fertilization rate (61% vs 61%) was not different between YS and G2 media. CONCLUSION: Immature oocytes seem to have a similar developmental competency in each of pyruvate dominant YS and glucose dominant G2 media containing human follicular fluid. Further investigations will be warranted to find the optimal media which can increase the developmental potential of immature oocytes.