Journal of Reproduction & Infertility

Journal of Reproduction & Infertility

Clinical Outcomes of Rescue Intracytoplasmic Sperm Injection at Different Timings Following In Vitro Fertilization

Authors
Yuki Shiraiwa 1
Noritoshi Enatsu 1
Kazuki Yamagami 1
Koyu Furuhashi 1
Toshiroh Iwasaki 1
Junko Otsuki 2
Masahide Shiotani 1
1 Hanabusa Women’s Clinic, Hyogo, Japan
2 Hanabusa Women’s Clinic, Hyogo, Japan; Okayama University Assisted Reproduction Technology Center, Okayama, Japan
10.18502/jri.v22i4.7650
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.
Keywords
Assisted Reproductive Techniques
Fertilization failure
In vitro fertilization
Infertility
Intracytoplasmic Sperm Injection
Journal of Reproduction & Infertility
Volume 22, Issue 4
Autumn 2021
Pages 251-257