Total motile count (TMC) is a useful tool for sperm evaluation, comprising both quantitative and motility parameters. Although frequently used, TMC has not yet been evaluated as a contributory variable for intracytoplasmic sperm injection (ICSI) cycles. In this study we evaluate the possible role of TMC as a prognostic parameter in cycles designated for ICSI. We also test the existence of a possible TMC-threshold value that might be predictive for ICSI cycle outcome in the everyday practice. This is a retrospective cohort study in which the research question is addressed by a locally weighted regression (LOESS) analysis. Primary outcome measures are fertilization rate, good quality embryos rate and implantation rate. A total of 666 patients were included, contributing 1456 cycles. The effect of TMC over the fertilization rate was significant, depicting an inverted U-shaped curve: with up to approximately 10 million motile sperm, fertilization rates increased as TMC increased, but from this point on decreased. A slight increment in the rate of good embryo formation with increasing value of TMC was noted, but this did not reach a statistical significance. TMC values demonstrated no effect in the case of implantation rates. ICSI may offer an advantage related to fertilization rates for the sub-fertile male population, with a motile sperm count up to 10 million.
Keywords: ICSI; Male infertility; embryo Implantation; fertilization; sperm motility.