RESUMO
PURPOSE: To compare the efficacy of gradient and swim-up semen preparation techniques on pregnancy rates in couples undergoing intrauterine insemination (IUI) cycles with low dose gonadotropin stimulation with the diagnosis of unexplained or mild male subfertility. METHODS: Two hundred and twenty three couples were randomized into swim up or gradient technique groups for sperm preperation. The clinical and on going pregnancy rates per cycle and per patient were evaluated. RESULTS: Both clinical and ongoing pregnancy rates per cycle were significantly higher in the "gradient" group (19% and 16.9%) in comparision with the "swim up" group (9.7% and 6.9%) (p < 0.05). Clinical pregnancy and on-going pregnancy rates per patient were higher in the "gradient" group (26.1% and 23.4%) when compared to the "swim up" group (15.2% and 10.7%), (p < 0.05). In the subgroup of 191 unexplained subfertile couples with 290 cycles; the "gradient" group also revealed significantly higher clinical and ongoing pregnancy rates per cycle (21.6% and 17.9%) when compared with the "swim up" group (10.3% and 7.1%) (p < 0.05). In total of 48 treatment cycles upon 32 couples with mild male factor subfertility no significant difference were found between the two sperm preparation techniques in terms of clinical (% 5.3 vs %6.9, p > 0.05) and ongoing (% 5.3 vs %6.9, p > 0.05) pregnancy rates per cycle. CONCLUSION: The gradient technique significantly improves clinical outcome in IUI cycles of unexplained subfertile couples when compared to swim up technique. In male subfertile patients, both techniques yield similar clinical outcomes.