Visualization of meiotic spindle and subsequent embryonic development in in vitro and in vivo matured human oocytes

Purpose The aim of this study is to investigate the relationship between spindle location and embryonic development of in vivo and in vitro matured human oocytes. Methods The spindles of 134 in vivo matured, 105 in vitro matured oocytes were examined by Polscope at the time of ICSI. Results The spindles were visualized in 83.6 and 77.1% of in vivo and in vitro matured oocytes respectively. The rate of fertilization of in vivo matured oocytes with spindles beneath or adjacent to the first polar body (angle of 0-5 degrees) was significantly higher (93.3%) than all other groups. The proportions of various spindle positions did not differ statistically in in vivo and in vitro matured oocytes. Conclusions Meiotic spindle location with regard to the first polar body appears to influence fertilization rate.