Abstract
We investigated how the visibility and position of the mitotic spindle which had undergone affects embryogenesis. The subjects were 830 oocytes at metaphase II intracytoplasmic sperm injection (ICSI). When the mitotic spindle was visible, oocytes were classified into the following groups according to its position: Group A, directly beneath the polar body; Group B, at 0‹< to ?45‹ clockwise from the polar body; Group C, at 45‹< to ?90‹; Group D, 90‹< to ?135‹; and Group E, 135‹< to ?180‹. When invisible, oocytes were classified into Group F. The percentage of Groups A to F were 57.4%, 38.5%, 3.5%, 0.5%, 0.1%, and 27.9%, respectively. The fertilization rate, the good embryogenesis rate, the blastocyst formation rate, and the good blastocyst formation rate of the visible oocytes (Groups A to E) were 70.6%, 48.3%, 41.5%, and 5.2%, respectively, and those of the invisible oocytes (Group F) were 65.9%, 47.7%, 29.5%, and 4.2%, respectively. The fertilization rate and the blastocyst formation rate tended to be higher for the visible oocytes. We confirmed that visualization of the mitotic spindle after ICSI is a meaningful method.
