TY - JOUR T1 - Clinical Outcomes of Rescue Intracytoplasmic Sperm Injection at Different Timings Following In Vitro Fertilization T2 - Journal of Reproduction & Infertility JT - Journal of Reproduction & Infertility SP - 251 EP - 258 VL - 22 IS - 4 PY - 2021 SN - 2251-676X L1 - https://www.jri.ir/documents/fullpaper/en/120137.pdf L2 - https://www.jri.ir/article/120137 UR - https://www.jri.ir/en/currentissue.aspx?id=89 PB - Avicenna Research Institute AU - Shiraiwa, Yuki AU - Enatsu, Noritoshi AU - Yamagami, Kazuki AU - Furuhashi, Koyu AU - Iwasaki, Toshiroh AU - Otsuki, Junko AU - Shiotani, Masahide AB -

Background: Although rescue intracytoplasmic sperm injection (r-ICSI) is extensively used worldwide, the indication of r-ICSI and its optimal timing remains obscure. This study aimed to assess the outcomes of r-ICSI following in vitro fertilization in different timings when fertilization is confirmed.
Methods: This study included 5,156 cycles (47,785 eggs). Fertilization was confirmed by polar body analysis after 4 and 6 hr of coincubation of the sperm and oocyte. Oocytes that underwent IVF were divided into two groups based on the time when a second polar body was detected in more than 30% of all oocytes (Four-hr group and six-hr group). If the second polar body was not detected or was present in less than 30% of all oocytes after six hr of coincubation, rescue-ICSI (r-ICSI) was performed for oocytes without a second polar body (r-ICSI group).
Results: The fertilization rates of two pronuclear (2PN) oocytes in the three groups (Four-hr group, six-hr group, and r-ICSI group) were 70.7%, 51.3%, and 58.0%, respectively. The blastocyst formation rates were 62.8%, 53.4%, and 42.9%, respectively.
Conclusion: Performing r-ICSI after six hr of coincubation can salvage cases with fertilization failure in IVF. The higher fertilization rate of r-ICSI indicates that all oocytes without signs of fertilization after six hr of coincubation should undergo r-ICSI.

CY - Tehran, Iran LA - English