Polarization microscopy and rescue ICSI.

A fraction of standard IVF cycles is afflicted by total fertilization failure. For several years, attempts have been made to develop strategies for rescuing these cycles in order to reduce the physical, psychological and economic burden imposed by an assisted reproduction technology treatment. Rescue ICSI is the approach by which failed fertilized oocytes can be microinjected on day 1 post insemination with the aim of achieving fertilization and thereby preventing cycle cancellation. In a study presented in this issue, Moon and colleagues perfected the rescue ICSI methodology by adopting polarized light microscopy as a tool to identify and treat only failed fertilized oocytes not penetrated by spermatozoa. In their experience, this approach generates a higher rate of normal fertilization. However, doubts concerning the safety of using failed fertilized, and therefore in-vitro aged, oocytes and the factual efficacy of rescue ICSI remain.