The effect of swim-up and gradient sperm preparation techniques on deoxyribonucleic acid (DNA) fragmentation in subfertile patients

To compare the effect of two different sperm preparation techniques, including swim-up and gradient methods on sperm deoxyribonucleic acid (DNA) fragmentation status of semen samples from unexplained and mild male factor subfertile patients undergoing intrauterine insemination (IUI). A prospective randomized study was conducted in 65 subfertile patients, including 34 unexplained and 31 male factor infertility to compare basal and post-procedure DNA fragmentation rates in swim-up and gradient techniques. Sperm DNA fragmentation rates were evaluated by a sperm chromatin dispersion (SCD) test in two portions of each sample of semen that was prepared with either swim-up or gradient techniques. Sperm motility and morphology were also assessed based on WHO 2010 criteria. Swim-up but not gradient method yielded a statistically significant reduction in the DNA fragmented sperm rate after preparation as compared to basal rates, in the semen samples of both unexplained (41.85 +/- 22.04 vs. 28.58 +/- 21.93, p < 0.001 for swim-up; and 41.85 +/- 22.04 vs. 38.79 +/- 22.30, p = 0.160 for gradient) and mild male factor (46.61 +/- 19.38 vs. 30.32 +/- 18.20, p < 0.001 for swim-up and 46.61 +/- 19.38 vs. 44.03 +/- 20.87, p = 0.470 for gradient) subgroups. Swim-up method significantly reduces sperm DNA fragmentation rates and may have some prognostic value on intrauterine insemination in patients with decreased sperm DNA integrity.