Prognostic value of meiotic spindle imaging on fertilization rate and embryo development in in vitro-matured human oocytes

Objective: To evaluate the relationship between spindle visualization and intracytoplasmic sperm injection (ICSI) outcomes in controlled ovarian stimulation (COS) cycles. Design: Prospective study. Setting: Assisted reproduction center. Patient(s): Thirty patients undergoing ICSI cycles. Intervention(s): Meiotic spindle was evaluated before ICSI in 234 in vivo- and 101 in vitro-matured oocytes Main Outcome Measure(s): Meiotic spindle imaging, fertilization rate, and embryo development. Result(s): Spindle was present in 74.3% and 73.8% of the in vivo- and in vitro-matured oocytes, respectively. Spindle detection rate in oocytes derived from germinal vesicle and metaphase-I stage was, respectively, 50% and 86%. The fertilization rate achieved by the in vivo-matured oocytes was 71.8%, and spindle was detected in 75.6% of the fertilized oocytes and only 34.8.% of the nonfertilized oocytes. In the in vitro-matured oocytes, the fertilization rate was 66.1 %, and spindle was detected in 81.4% of the fertilized oocytes and in 59.1 % of the nonfertilized oocytes. Ten out of 43 (23.2%) in vitro-matured derived embryos were considered to be high quality, all derived from spindle-detected oocytes, which represents in increase of 13.0% on the overall number of high-quality embryos. Conclusion(s): Meiotic spindle imaging may be useful to predict in vitro-matured oocyte development. However, other factors may contribute to the decreased developmental competence of in vitro-matured oocytes.