Are sperm chromatin and DNA defects relevant in the clinic?

There has been an increase in the use of sperm DNA and chromatin integrity tests in the evaluation of the infertile man with the hypothesis that these tests may better diagnose infertility and predict reproductive outcomes. This review discusses the etiology of sperm DNA damage, briefly describing the tests of sperm DNA damage, and evaluates the relationship between sperm DNA damage and reproductive outcomes. A systematic review of the literature allows us to conclude that sperm DNA damage is associated with lower natural, intra-uterine insemination (IUI), and in vitro fertilization (IVF) pregnancy rates. Studies to date have not shown a clear association between sperm DNA and chromatin defects and pregnancy outcomes after intra-cytoplasmic sperm injection (ICSI). However, we cannot exclude the possibility that very high levels of DNA damage will impact on ICSI outcomes. In couples undergoing IVF or ICSI, there is evidence to show that sperm DNA damage is associated with an increased risk of pregnancy loss. A limitation of this systematic review and meta-analysis is that it does not address the heterogeneity of the individual study characteristics. Although the clinical utility of tests of sperm DNA damage remains to be firmly established, the data suggest that there is clinical value in testing couples prior to assisted reproductive technologies (ARTs IUI, IVF, and ICSI) and in those couples with recurrent miscarriages. Additional, well-designed prospective studies are needed before testing becomes a routine part of patient care.