ICSI for non-male factor infertility: time to reappraise IVF?

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.