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

Abstract 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.