Fertility & Reproduction (Dec 2023)

#267 : The Spindle Localization ICSI (SL-ICSI) Improves the Fertilization Rate Decreased by Aging

  • Hiroomi Kawano,
  • Aya Takai,
  • Mutsumi Abe,
  • Yuki Iimura,
  • Naotsuna Nakajima,
  • Mo Chen,
  • Azusa Ochi,
  • Akihiro Yamauchi,
  • Mari Shinoda,
  • Masato Yoshida,
  • Naoki Yamashita

DOI
https://doi.org/10.1142/S2661318223741747
Journal volume & issue
Vol. 05, no. 04
pp. 373 – 373

Abstract

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Background and Aims: The position of meiotic spindle in metaphase II oocyte can be different from the underneath of the first polar body. In order to prevent the meiotic spindle damage during ICSI, confirming the position of the spindle is effective. In this study, we analyzed the meiotic spindle deviation and outcomes of ICSI with the patient age. Method: From 2017 to 2022, 5620 oocytes with the first polar body underwent SL-ICSI were analyzed. SL-ICSI was performed 4-5 hours after oocyte retrieval. Furthermore, the meiotic spindle deviation from the polar body was classified according to the angle; Group A: 0-5∘, Group B: 6-45∘, Group C: 46-90∘, Group D: 90∘<. The spindle invisible oocytes were regarded as group E. The average age, the fertilization rate and good blastocyst rate in each group were analyzed. Statistical analysis was performed by one-way ANOVA and Tukey’s post-hoc test. Results: The proportions of spindle-visible oocyteswere 98.7%; 41.2%, 36.1%, 14.6%, 6.8%, and 1.3% respectively, in group A to E. The mean agesin each group were 39.0, 39.6, 40.1, 40.6, and 40.7, respectively. In addition, the correlation between the age and the location of spindle was revealed (A-BCDE: [Formula: see text] < 0.001). The fertilization rates were 84.8%, 84.9%, 84.7%, 83.5%, 50.7%, respectively, and significantly decreased in group E ([Formula: see text] < 0.001). Abnormal fertilization rates were 4.3%, 5.1%, 6.4%, 7.3%, 20.5%, respectively, and significantly increased in group E ([Formula: see text] < 0.001). Good blastocyst rates were 49.8%, 52.4%, 47.6%, 50.5%, 3.3%, respectively, and significantly decreased in group E ([Formula: see text] < 0.001). Conclusion: The introduction of SL-ICSI can be effective for elderly patients. The meiotic spindle of oocytes is highly likely to deviate from the first polar body by aging. Furthermore, if the spindle-invisible oocyte is observed, ICSI should be carefully carried out.