What Is DNA Fragmentation Index?
Typically, the chances of infertility being attributed to the male partner are between 35% and 40%. The development of a healthy embryo is initiated when the chromosomes in the egg unite with the chromosomes in the sperm. These chromosomes consist of strands of DNA (deoxyribonucleic acid). The function of the sperm is to deliver male DNA to the egg; the quality of DNA delivered can determine the development of the embryo and subsequent milestones during pregnancy.
Why Is It Important to Check DNA Fragmentation Index?
Traditionally, methods of evaluation of male infertility were limited to a semen analysis that measured the count, motility, and morphology of sperm. It did not assess the DNA that was being delivered. The truth is, sperm that appears normal in terms of motility and morphology by traditional semen analysis, may exhibit significant DNA fragmentation. Up to 8% of infertile men have high levels of sperm DNA fragmentation despite demonstrating normal semen in tests. Thus, it is very important to gauge DNA fragmentation in sperm, to assess male fertility. Recent studies suggest that sperm with DNA fragmentation beyond a certain threshold are evidence of compromised male fertility. The degree of DNA fragmentation in sperm is measured using a metric called the DNA Fragmentation Index (DFI).
Sperm DNA fragmentation is usually tested using a procedure called the sperm chromatin dispersion test (SCD). In this routine, around 500 sperm cells are analysed and graded as per the size of their halos. Normal sperm without DNA fragmentation have halos that range in size from medium to large. Sperm that display a small or no halo point to fragmented DNA. A normal sample is thought to hold less than 15% of sperm with DNA damage.
All men diagnosed with abnormal semen are ideal candidates for this test, as are those with normal semen and unexplained infertility, previous failed intrauterine insemination cycles or failed in vitro fertilisation procedures.
Causes of Sperm DNA Damage
- Drugs, chemotherapy and radiation therapy
- Cigarette smoking
- Environmental toxins
- Genital tract inflammation
- Testicular hyperthermia (use of hot baths, saunas, laptop computers and prolonged periods of driving)
- Infrequent ejaculation
- Advanced age
Treatment for Sperm DNA damage
Depending on what caused the damage to the sperm DNA, there may or may not be a way to enhance sperm DNA. Some ways that may help improve sperm DNA include lifestyle changes, abandonment of cigarettes, reduced exposure to toxins, and consumption of daily zinc and antioxidant supplements. Other specialised clinical options may be suggested by your fertility specialist.
Authored by Dr. Uma Maheswari
Cloudnine Fertility – JP Nagar