Objectives: The present study focused on tobacco smoke and its effect on semen parameters, sperm DNA quality (compaction and fragmentation) and clinical outcomes after intracytoplasmic sperm injection (ICSI) therapy.

Materials and Methods: The semen samples were divided according to smoking status into the following 2 groups, 98 heavy-smokers (G1) and 43 non-smokers (G2). Semen was prepared and purified using the PureSperm gradients according to the WHO guidelines 2010. Protamine deficiency (CMA3 positivity) was assessed by chromomycin CMA3 staining and sperm DNA fragmentation (sDF) by TUNEL assay.

Results: The mean concentration and the total motility were significantly higher in G2 in comparison to G1 (P = 0.014, and P = 0.026 respectively) and the results were similar for the mean percent of the progressive motility and normal morphology (P = 0.0001). CMA3+ and sDF in G2 were significantly lower in comparison to G1 (20.35 ± 13.34% vs. 33.30 ± 22.33%, P = 0.001; 14.23 ± 13.07% vs. 26.68 ± 19.77%, P = 0.0001). Meanwhile, there were no significant differences in the ICSI outcomes, except for the pregnancy rate, which was significantly higher in G2 than in G1 (0.60 ± 0.49% vs. 0.38 ± 0.48%; P = 0.013). In G1, CMA3+ correlated negatively with sperm concentration (r = -0.233, P = 0.021) but positively with sDF (r = 0.484, P = 0.0001). In G2, sDF correlated negatively with progressive motility and morphologically normal spermatozoa (r = -0.304, p=0.047; r = -0.361, P = 0.017 respectively).

Conclusions: The findings of this study revealed that tobacco smoking altered sperm parameters and later affected the pregnancy results in ICSI therapy. CMA3 and TUNEL tests are therefore useful as a supplementary test before any ART treatment to ensure a good prognosis.