Failed fertilization with conventional oocyte insemination can be overcome with the ability of ICSI according to binding or failing to bind to the zona pellucida
To determine the frequency of failed fertilization with conventional oocyte insemination and to determine the ability of intracytoplasmic sperm injection (ICSI) to overcome the failed fertilization according to binding or failing to bind to the zona pellucida. Materials and Methods: Retrospective review of 12,448 in vitro fertilization (IVF) cycle to identify cycles where failed fertilization occurred following conventional oocyte insemination with seemingly normal sperm. A number of three oocytes retrieved was required. Results: There were only 12 cases of failed fertilization (0.1%). Six were related to failure of any or few sperm attaching to the zona pellucida These six had high fertilization rates with ICSI. Six had normal attachment and five attempted another cycle, this time with ICSI. Only 60% had good fertilization. Conclusions: When there is failed fertilization with normal sperm oocyte binding following conventional oocyte insemination, ICSI may still be effective in 60% of the cases, but it would be probably recommended to combine ICSI with artificial oocyte activation by calcium ionophore.