The researchers looked at using a rescue method called intracytoplasmic sperm injection (ICSI) 16-20 hours after insemination when regular IVF failed to fertilize eggs. They studied 243 cycles of 211 patients and found that the rescue ICSI group had lower fertilization rates and embryo quality compared to direct ICSI. However, when using frozen-thawed embryos, both groups had similar success rates. The study suggests that using rescue ICSI in certain cases may lead to better pregnancy outcomes.