Shiraiwa Y, Enatsu N, Yamagami K, Furuhashi K, Iwasaki T, Otsuki J, Shiotani M. Clinical Outcomes of Rescue Intracytoplasmic Sperm Injection at Different Timings Following In Vitro Fertilization.
J Reprod Infertil 2022;
22:251-257. [PMID:
34987986 PMCID:
PMC8669413 DOI:
10.18502/jri.v22i4.7650]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 03/15/2021] [Indexed: 11/24/2022] Open
Abstract
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.
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