What is Sperm DNA Fragmentation?
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Simply put, sperm DNA fragmentation is when a series of breaks occurs in the strands of DNA within a sperm. The sole job of sperm is to deliver the genetic information (the DNA) of the father to an egg. When a significant percentage of sperm have DNA damage, the likelihood that the genetic information is properly delivered to the egg decreases.
The body has many specialized processes in which DNA damage is identified and repaired. Our cells constantly repair DNA damage via specialized enzymes that excise areas of injury and replace them with the appropriate DNA building blocks. However, sperm are unique in that mature sperm cells do not have the ability to identify and repair damaged DNA.
A laboratory test known as the DNA Fragmentation Index (DFI) determines the percentage of sperm with significant DNA fragmentation. Men with an elevated DFI, often considered to be 30% or greater, have been shown in multiple studies to have problems with fertility. These problems can include the inability to conceive a pregnancy, taking longer than average to conceive, or recurrent pregnancy losses (i.e., miscarriages). Research shows that an elevated DFI is associated with abnormalities in the sperm themselves. Men with an elevated DFI are more likely to have lower sperm motility and abnormal morphology.
Additionally, men with elevated DFI are less likely to have success with assisted reproductive technology such as intrauterine insemination (IUI) and in vitro fertilization (IVF).
What can increase sperm DNA fragmentation?
There are several factors that can increase DFI. A common anatomic factor associated with elevated DFI are varicoceles. Varicoceles are dilated veins within the spermatic cord, which is the structure on which each testicle hangs. The veins of the spermatic cord take blood away from the testicle back toward the heart. These veins are dilated in about 15% of males, which leads to reflux of blood back into the testicle. The increased pressure and temperature caused by this blood has been shown to increase sperm DFI. Varicoceles are diagnosed via physical exam or an ultrasound, and are repaired with a minor surgery. The repair of varicoceles can lower sperm DFI.
Lifestyle factors can also increase sperm DFI. These include smoking, binge drinking, and lack of exercise - which is why these lifestyle changes are extremely important. .
However, many other things that are outside of our control (like genetics and other unknown factors) are major contributors to increased DNA fragmentation in men.
*This post is for educational purposes only, and should not be taken as medical advice. If you have personal medical questions, consult with your personal physician*