Relationship of within-patient semen variability to outcome of intrauterine insemination

To define the subpopulation of infertility patients who would benefit from intrauterine insemination (IUI) with swim-up homologous sperm, the relationship of within-patient semen variability to outcome of IUI was studied. The 61 women in the study had negative workups. Men had at least one semen sample with ≥ 20 x 10⁶ sperm/ml. The 6-month cumulative pregnancy rate for all patients was 31.8%. Patients with original sperm motilities consistently ≥30% had a higher cumulative pregnancy rate (62.9%) than patients with one or more motility < 30% (22.0%, P = 0.0015, log-rank test). Patients with post-swim-up motilities consistently ≥ 70% had a cumulative pregnancy rate (51.2%) significantly greater than patients inconsistent for this parameter (15.6%, P = 0.0116). Consistency of sperm motility is a useful parameter for defining the subpopulation of patients who would benefit from IUI.