Prospective evaluation of the impact of sperm characteristics on the outcome of intra-uterine insemination

Thresholds of sperm parameters associated with intrauterine insemination (IUI) success are controversial. This entails heterogeneous practices and leads to low success rate (approximately 8% per attempt). The aim of this study was to evaluate the influence of sperm parameters on the outcome of IUI. This study included 248 cycles of IUI. Parameters of the raw and selected sperm, as well as the main female characteristics, have been prospectively tabulated and compared, according to the presence or not of a clinical pregnancy. In all, 28 clinical pregnancies were obtained (11.3% per cycle). Thresholds of 10% for the forward motility "a" in the whole sperm and of 20% for the percentage of typical spermatozoa in the selected sperm were related to the success of IUI. The number of motile inseminated spermatozoa, concentration and overall motility of sperm, determined before or after selection, did not have any significant influence on the outcome of IUI. Thresholds determined in our study should help to optimize the use of IUI.