Comparison of in vitro maturation media of immature oocytes: the effectiveness of blastocyst culture media

Objective: To compare three different in vitro maturation (IVM) media for immature oocytes. Design: Experimental study. Setting: In vitro fertilization laboratory. Animal(s): BDF1 female and male mice. Intervention(s): Retrieval and maturation of cumulus-enclosed germinal vesicle-stage oocytes according to one of three protocols: group A, conventional IVM medium; group B, blastocyst culture medium; and group C, tissue culture medium (TCM) 199. Main Outcome Measure(s): Maturation, fertilization, and developmental rates of immature oocytes. Result(s): A total of 653 immature oocytes were cultured in vitro and then analyzed. No difference was found in maturation rates and fertilization rates in comparing groups A and B. However, the IVM rates were statistically significantly increased in groups A and B compared with group C. No difference was found in fertilization rates between media, but the developmental competency to blastocyst stage was statistically significantly higher in group B compared with group C. Conclusion(s): The developmental competency of immature oocytes did not differ between conventional IVM medium and blastocyst culture medium, but TCM-199 was found to be unsuitable. Evidence from mice as test subjects suggests that both conventional IVM medium and blastocyst culture medium are suitable for IVM, and that blastocyst culture medium may be a good choice for conventional IVM of immature oocytes. (Fertil Steril (R) 2011;95:554-7. (C) 2011 by American Society for Reproductive Medicine.)