Correlation of sperm DNA damage with IVF and ICSI outcomes: A systematic review and meta-analysis

To assess the effects of sperm DNA damage, as determined by the TUNEL assay and the SCSA respectively, on the outcomes of IVF/ICSI treatment.A Medline search (from Jan 1978 to Apr 2006) was performed, together with a manual search of the bibliographies of retrieved original papers and review articles. 8 articles met all inclusion/exclusion criteria, of which, 5 used the TUNEL assay and the other 3 used the SCSA. All these articles were included in separate meta-analysis. The meta-analysis was conducted using the RevMan software with fixed-effect model or random-effects model.As for articles using the TUNEL assay, the pooled results of IVF outcomes indicated that the clinical pregnancy rate (RR 0.68, 95% CI 0.54 to 0.85, P = 0.006), but not the fertilization rate (RR 0.79, 95% CI 0.54 to 1.16, P = 0.23) decreased significantly for patients with high degree of sperm DNA damage compared with those with low degree of sperm DNA damage. RRs of the ICSI outcomes indicated that there was no significant difference in either fertilization rate (RR 1.03, 95% CI 0.89 to1.18, P = 0.70) or clinical pregnancy rate (RR 0.76, 95% CI 0.55 to 1.04, P = 0.09) between these two groups. As for the SCSA papers, the pooled results showed no significant effects of sperm DNA damage on the clinical pregnancy rate after IVF (RR 0.58, 95% CI 0.25 to 1.31, P = 0.19) or ICSI (RR 1.18, 95% CI 0.81 to 1.74, P = 0.38).Our meta-analysis indicates that sperm DNA damage, as assessed by the TUNEL assay, significantly decreases only the chance of IVF clinical pregnancy, but not that of either IVF fertilization or ICSI fertilization or ICSI clinical pregnancy. Besides, our results also reveal that sperm DNA damage, when assessed by the SCSA, has no significant effect on the chance of clinical pregnancy after IVF or ICSI treatment.