Comparison of sperm preparation methods: effect on chromatin and morphology recovery rates and their consequences on the clinical outcome after in vitro fertilization embryo transfer

The aim of this study was to evaluate the efficacy of swim-up, PureSperm(R) gradient centrifugation and glass-wool filtration methods for semen prepar ation and to assess the possible enhancement of the quality of the subpopul ation of spermatozoa in terms of sperm concentration, morphology and chroma tin condensation. Moreover, to determine the effect of this semen processin g technique on the clinical outcome after in vitro fertilization embryo tra nsfer (IVF-ET). A total of 180 semen samples of patients' husbands who were undergoing IVF therapy were prepared by swim-up (G1, n = 60), PureSperm(R) gradient centri fugation (G2, n = 60) or glass-wool (G3, n = 60) methods. Chromatin condens ation was assessed by Chromomycin (CMA3), whereas sperm morphology was eval uated according to strict criteria. In all three semen processing methods, the percentage of chromatin condensed and morphologically normal spermatozo a was higher after semen processing in comparison with native semen samples . The proportion of normal chromatin condensed spermatozoa prepared in glas s-wool filtration was significantly higher than that in swim-up (G.I, p = 0 .02) or PureSperm(R) (G.II, p = 0.001). In addition semen processing with P ureSperm(R) yields significantly a higher percentage of morphologically nor mal spermatozoa than swim-up (p < 0.001) or glass-wool method (p < 0.002). However, the fertilization, implantation and pregnancy rates, in turn were similar in all semen preparation methods. In conclusion, PureSperm(R) gradient centrifugation yields a higher percent age of morphologically normal spermatozoa than shown in traditional swim-up or glass-wool filtration. However, the percentage of chromatin condensed s permatozoa was significantly higher after semen processing via glass-wool i n comparison with the other two methods. Nevertheless, there were no significant difference in the fertilization, im plantation and pregnancy rates of sperm prepared by means of swim-up, PureS perm(R) or glass-wool filtration. Therefore, glass-wool filtration should be recommended as the first choice for semen preparation for Intracytoplasmic sperm injection (ICSI) technique as the natural selection is bypassed. Whereas, swim-up and PureSperm shoul d be used for semen processing in IVF programme.