Semen quality before and after processing by a swim-up method: relationship to outcome of intrauterine insemination.

Twenty-five couples with normal semen analyses and postcoital tests of less than or equal to 3 motile sperm/high-power field were treated by intrauterine insemination (IUI) with sperm prepared by a swim-up method. Eight women conceived (32%). Influence of semen parameters both before and after swim-up, patient age, and duration of infertility on outcome of IUI was assessed with logistic discriminant analysis. The percent motility of sperm after swim-up allowed significant differentiation of pregnant and nonpregnant patients (P = 0.0009). For patients with greater than 79% motility after swim-up, discrimination provided by post-swim-up motility (P = 0.0063) was enhanced by inclusion in the analysis of either total number of motile sperm used for insemination (P = 0.0021) or sperm concentration after swim-up (P = 0.0019), Predictions of nonpregnancy and pregnancy were correct at rates of 93.3 and 70%, respectively. There were no significant differences between semen parameters of conception and nonconception cycles of patients who conceived.