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Intracytoplasmic sperm injection (ICSI) was initially introduced to overcome problems due of severe male factor infertility not being solved with conventional in-vitro fertilization (cIVF). However, recent years have witnessed an increasing use of ICSI by most assisted reproductive technique laboratories for non-male factor indications. Examples of the latter include previous fertilization failure after cIVF, few or poor-quality oocytes, immature oocytes, advanced maternal age, preimplantation genetics test (PGT), cryopreserved oocytes, and unexplained infertility. The replacement of cIVF with ICSI in several non-male factor infertility cases is probably because some reproductive specialists consider that ICSI is associated with better reproductive outcomes. Unfortunately, data on reproductive outcomes in favor of ICSI over cIVF are limited or absent. Therefore, the factors that can help define the use of one technique over the other should be identified. These should include the likelihood of fertilization failure, potential risks of the procedure, and its costs. In this review, we aim to highlight the current guidelines, advantages, and limitations of the use of cIVF/ICSI for infertility treatment. Additionally, we provide a comprehensive review of the use of ICSI in indications other than severe male factor infertility.

Male infertility is attributed to multiple factors including high levels of sperm DNA fragmentation (SDF). Conventional semen analysis continues to be the gold standard for diagnosis of male factor infertility around the world. However, the limitations of basic semen analysis have prompted the search for complementary assessments of sperm function and integrity. Sperm DNA fragmentation assays (direct or indirect) are emerging as important diagnostic tools in male infertility workups, and have been advocated for use in infertile couples for a variety of reasons. While a controlled degree of DNA nicking is required for appropriate DNA compaction, excessive fragmentation of sperm DNA is linked to impaired male fertility potential, decreased fertilization, poor embryo quality, recurrent pregnancy loss, and failure of assisted reproductive technology procedures. However, there is an ongoing debate regarding whether or not to employ SDF as a routine test for male infertility. This review compiles up-to-date information regarding the pathophysiology of SDF, the currently available SDF tests, and the role of SDF tests in natural and assisted conception conditions.

The body of evidence supports the negative impact of increased sperm DNA fragmentation (SDF) on natural fertility as well as assisted reproduction conditions. High SDF has been correlated with low pregnancy and delivery rates following intrauterine insemination. Also, high SDF is accused of reducing the rates of fertilization, implantation, pregnancy, and live birth following in-vitro fertilization (IVF). Despite no impact of high SDF on fertilization or pregnancy rates following intracytoplasmic sperm injection (ICSI), it has been correlated with poor embryo quality and a higher risk of miscarriage. Several methods have been introduced to help select sperm with the best DNA quality to be used in assisted reproductive technology procedures. These include magnetic-activated cell sorting, intracytoplasmic morphologically selected sperm injection, physiologic ICSI, and microfluidic sperm sorters, among others. This article aimed to discuss the impact of high SDF in infertile men on the reproductive outcome of couples undergoing IVF/ICSI. Additionally, this review highlights the principles, advantages, and limitations of different techniques that are currently used for the selection of sperm with intact DNA to be utilized for ICSI.