In vitro maturation of germinal vesicle oocytes in stimulated intracytoplasmic sperm injection cycles

ABSTRACT

This study evaluated in vitro maturation [IVM] of oocytes in the germinal vesicle [GV] stage in stimulated intracytoplasmic sperm injection [ICSI] cycles. A total of 26 women, aged 18-37 years, who were candidates for ICSI at the Fatemeh Zahra Infertility and Health Reproductive Research Center in 2007 were recruited for this study. We used the standard long protocol for ovarian stimulation. Follicles>11 mm were punctured 36-38 hours after administration of 10000 IU human chorionic gonadotrophin [hCG]. Immature oocytes were cultured for 24-30 hours. Oocytes that liberated polar bodies were injected by sperm prepared within the previous day. IVM fertilized oocytes were cultured an additional 24-30 hours for cleavage. The rates of maturation, fertilization and cleavage in IVM oocytes were recorded and statistically compared to in vivo matured sibling oocytes. There were 279 collected oocytes [mean +/- SD 10.73 +/- 6.2], of which 4.08 +/- 2.79 were subjected to IVM. An average of 2.73 +/- 2.15 GV oocytes [70%] developed to metaphase II [MII]. Although the maturation rate significantly differed between the IVM and in vivo MII sibling oocyte groups [p=0.027], the numbers of fertilized oocytes [p=0.795] and cleaved embryos [p=0.529] were not significantly high in the in vivo group. Transfer of IVM embryos occurred in only three cases with one pregnancy that resulted in the delivery of a healthy baby. This study shows that culturing GV oocytes can produce acceptable numbers of four-cell embryos on the transfer day. The developmental competence of oocytes is not significantly different between early stage IVM and in vivo sibling embryos