Sperm DNA fragmentation refers to damage of the genetic material of the spermatozoa. In order to detect the presence of abnormal spermatozoa and assess the percentage of damaged DNA, specific tests called “fragmentation” tests are carried out. The examination of the seminal fluid, the spermiogram, is useful for assessing other important parameters, including the morphology of the spermatozoa.
The causes of these abnormalities can be either internal or external. In the latter case, triggering factors include the production of free radicals during sperm transport, episodes of high fever, acute inflammatory diseases and exposure to high temperatures. In such situations, the percentage of sperm with fragmented DNA can be reduced by antioxidant-based therapies.
In some cases, however, the cells themselves can spontaneously correct any abnormalities. These repair mechanisms are also present in gametes, and sometimes the egg cell is also able to repair the damage to the DNA of the sperm that fertilised it. The likelihood of this happening depends on the type and number of lesions in the genetic material, the percentage of compromised DNA and the quality of the oocyte.