Is Sperm DNA Fragmentation Testing still relevant in Male Infertility diagnosis?

Semen analysis is important as a basic test to value male infertility. However, it alone cannot accurately predict infertility. Additional tests are required to review and evaluate abnormalities in the sperm. One of these is SDF (Sperm DNA fragmentation) testing.

SDF means there is abnormal genetic material within the sperm. It occurs when there is a break – single stranded or double stranded – in each cell of the male reproductive gamete/cell or sperm. The mature male cell is unable to repair the damage to the DNA which sometimes affects the male reproductive system.

Causes: There are 3 main causes for SDF.

  • Apoptosis: where cells die before completing the process of development and are released with DNA fragmentation due to endonucleases (enzymes which cut DNA).
  • Oxidative stress: is produced by ROS (reactive oxygen species) which is an unstable molecule containing oxygen and which easily reacts with other molecules in a cell, causing damage to DNA resulting in either single or double-stranded breaks. This can occur in the testes or as the spermatozoa move within the male reproductive tract. It can also occur after ejaculation during the processing of the sperm for various procedures or during cryopreservation (storing and cooling cells at very low temperatures). Many external factors also give rise to reactive oxygen species like lifestyle/environmental factors, chemicals etc.
  • Defective chromatin maturation: During spermatogenesis (the development of mature spermatozoa), the chromatin (substance within a chromosome consisting of DNA and protein) does not mature properly and damages are not repaired, leading to less compact DNA which is not well protected against damage by exogenous elements.

Despite assisted reproductive technologies (ART), SDF levels can be associated with negative outcomes. Pregnancies and delivery rates after IUI (intrauterine insemination) have been affected by high SDF values. SDF can also play a part in increased miscarriage and lower pregnancy rates for IVF (in vitro fertilization) and ICSI (intracytoplasmic sperm injection). Varicoceles which are enlarged veins which develop in the scrotum can impair the flow of blood from the testicles to the reproductive system. SDF is found to be higher in males with varicoceles. Elevated SDF levels also affect male genital tract infection.

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In the case of an infection, like male genital tract infection which would give rise to elevated levels of ROS, antibiotics can be used which can cure the underlying infection and thereby reduce elevated SDF levels. Varicocelectomy is a surgery where the enlarged veins in the scrotum are removed. This improves the SDF result. Some lifestyle changes can improve SDF levels – no smoking, giving up alcohol, weight reduction and keeping aloof from radiation and exposure to environmental toxins. These include not only physical (drugs, chemicals, paints) but emotional as well (unemployment, insecurity, fear, uncertainty and humiliation). Also, it is reported that shorter ejaculatory abstinence time shows reduction in SDF levels. Studies show that antioxidants reduce SDF damage. Testicular sperm is less exposed to epididymis and external oxidative stress and is felt to have reduced SDF compared with ejaculated sperm.

Given the above impact of SDF on male Infertility and pregnancy outcomes, testing for Sperm DNA Fragmentation is indeed extremely relevant in patients with the above mentioned indications. While SDF testing may not be routinely recommended, there are many patients who can benefit from an SDF test with regards to their further fertility treatments and in some cases provide explanations for previous failed fertility treatments as well. We can therefore with confidence say that an important factor while evaluating male infertility is SDF testing.

We, at Andrology Centre, use the SCSA method of testing, as it has been proven to quickly and accurately identify men who may or may not, either naturally or with ART techniques, be able to achieve a successful pregnancy. The SCSA method determines the amount of sperm with DNA fragmentation and the degree of DNA damage. The results of this test help in clinical diagnosis and management, assisting the couple in deciding on what steps to take next.