Clinical outcomes of MII oocytes with refractile bodies in patients undergoing ICSI and single frozen embryo transfer

Hiromi Takahashi, Junko Otsuki, Michio Yamamoto, Hiroe Saito, Rei Hirata, Toshihiro Habara, Nobuyoshi Hayashi

Research output: Contribution to journalArticle


Purpose: This study aimed to analyze whether the presence of refractile bodies (RFs) negatively affects fertilization, embryo development, and/or implantation rates following intracytoplasmic sperm injection (ICSI). Methods: This retrospective embryo cohort study involved a total of 272 patients undergoing ICSI treatment of blastocyst cryopreservation. Results: In the study, no significant differences were found regarding 2PN formation rates between RF(+) (76.5%) and RF(−) oocytes (77.2%). However, the blastocyst formation rate on Day 5 in RF(+) oocytes was 45.8%, which was significantly lower than that of 52.2% in RF(−) oocytes (aOR 0.74, 95% CI 0.59-0.93, P =.011). Implantation rates were also significantly lower in RF(+) oocytes (24.2%) as compared to RF(−) oocytes (42.2%) (aOR 0.46, 95% CI 0.26-0.78, P =.005). Furthermore, the implantation rate of RF(+) oocytes (28.6%), when high-quality blastocysts were transferred, was significantly lower than that of RF(−) oocytes (46.1%) (aOR 0.50, 95% CI 0.25-0.96, P =.043). Conclusion: Our results suggest that oocytes with the presence of RFs have a lower potential for blastocyst development. Even when they develop into high-quality blastocysts, the chances of implantation are reduced.

Original languageEnglish
JournalReproductive Medicine and Biology
Publication statusAccepted/In press - Jan 1 2019



  • blastocyst
  • cytoplasmic morphology
  • embryo implantation
  • ICSI
  • refractile body

ASJC Scopus subject areas

  • Reproductive Medicine
  • Cell Biology

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