Objective: To analyze the relationship between meiotic spindle location and embryo developmental potential of in vivo and in vitro matured human oocytes.
Methods: One hundred and thirty-four in vivo matured oocytes and 45 in vitro matured oocytes were observed with polscope at the time of intracytoplasm sperm injection (ICSI).
Results: Meiotic spindle was detected in 83.6% (112/134) and 82.2% (37/45) in in vivo and in vitro matured oocytes respectively. In vivo matured oocytes which showed a minimal angle (0-5 degrees ) between the meiotic spindle and the first polar body had a higher fertilization rate (93.3%) than the others. The frequency of the oocytes which had a 0-5 degrees spindle angle in in vivo and in vitro matured oocytes was 22.4% and 17.8%, respectively, and that of oocytes which had a 6 degrees - 45 degrees, 46 degrees-90 degrees and > 90 degrees spindle angle was 55.2% vs 51.1%, 3.0% vs 8.9%, and 3.0% vs 4.4%. No significant difference was found between them. No relationship was found between the position of meiotic spindle and embryo quality.
Conclusions: There is some relationship between the angle of the meiotic spindle with the first polar body and fertilization rate. No significant difference is found in the position of the meiotic spindle between in vivo and in vitro matured human oocytes.