Abstract: Objective: To Analyze the relation between the sperm parameters and cleavage rate, the quality of embryos and the pregnancy rate, investigate the impact of sperm morphology on spermatozoal functions in in-vitro-fertilization. Methods: We only included couples whose fertilization rate was 100%. A total of 82 cycles were included in our study. Before and after density gradient centrifugation, sperm morphology was evaluated by Diff-Quik stain according to the WHO criterion. The normal proportion of normal morphology sperm is ≥14%, and ＜14% is abnormal. Investigate and analyze the change of sperm parameters before and after density gradient centrifugation, female patient’s age, endometrium thickness, and sperm parameters. Compare morphology, normal fertilization rate, cleavage rate, the quality of embryos and the pregnancy rate between two groups before and after sperm preparation. Results: ①After density gradient centrifugation, all of 82 samples semen density reduced and sperm motility improved significantly. ②Before sperm preparation, 11 samples（13.41%）were normal and 71 (86.59%) were abnormal; after preparation, 34（41.46%）samples were normal and 48（58.53%）were abnormal. The normal proportion of normal morphology sperm of abnormal samples improved obviously（P ＜0.01）, median（P25, P75） are 8.15%（6.38%, 10.50%）vs. 12.41% （9.98%, 18.58%）. ③There are no significant difference in density and motility between normal and abnormal groups before spem preparation（P ＞0.05）. ④Follow up analysis showed that the normal group had no higher clinical pregnancy rate and higher quality embryos rate （P ＞0.05） but higher cleavage rate（P ＜0.05）than the abnormal one. ⑤There were no significant differences for endometrium thickness and sperm parameters except the couples age between two groups of pregnancy or not. Conclusion: There is no significant prognosis of human normal morphology sperm rate on pregnancy outcomes of IVF-ET. Density gradient centrifugation can increase the normal morphology sperm percentage. The selection of the insemination methods should be made according to the results after density gradient centrifugation.

Key words: nfertility, Spermatozoa, Semen, Reproductive techniques, assisted, Centrifugation, Pregnancy outcome