Sperm DNA Fragmentation Testing and Fertility

Sperm DNA fragmentation testing may be recommended in certain cases where fertility is compromised. The test is used to evaluate the quality of sperm DNA. Embryos that develop from sperm that carries damaged (fragmented) DNA are less likely to survive.

WHAT IS SPERM DNA FRAGMENTATION?

Deoxyribonucleic acid, or DNA, is the genetic material that contains the instructions required for an embryo to develop and survive. Each DNA molecule has two strands and four bases (molecule types that connect to the strands). The bases act as building blocks since they always follow the same order, or sequence, when connecting the two strands.

When one or both DNA strands contained in sperm is broken, it can lead to infertility or compromise the health of the embryo.

SPERM DNA FRAGMENTATION TESTING

Nearly half of infertility cases involve some level of male factor infertility and there is reason to suspect some unexplained infertility case may be linked to sperm DNA fragmentation.

Sperm DNA fragmentation testing is not part of a routine semen analysis even though the method of collection is the same for the two tests. However, sperm samples for both tests may be obtained from the same specimen. After a sperm sample is collected at a fertility clinic, a portion of the specimen is frozen and sent to a specialty lab for sperm DNA fragmentation testing.

On examination, sperm quality is determined by DNA integrity, which is measured by counting the number of breaks in the double strand DNA structure. A high level of sperm DNA fragmentation may contribute to infertility.  Even when conception does occur, highly fragmented sperm DNA may negatively affect embryo development and decrease the chances of a successful pregnancy.

Clinical results fall into three categories:

• 15 percent DFI or less = Excellent fertility potential
• 15 – 25 percent DFI = Good to fair fertility potential
• 25 percent or higher = Fair to poor fertility potential

SPERM DNA FRAGMENTATION CAUSES

There are a number of factors that can contribute to sperm DNA fragmentation but the number one cause is thought to be oxidative stress. This occurs when free radicals build-up and the body is unable to neutralize them. Other contributing causes include:

• Infection
• Obesity
• Varicocele
• Environmental or occupational toxins
• Advanced age
• Drug use
• Smoking
• Poor diet
• Increased testicular temperature
• Illnesses that produce high fevers
• Chronic disease

TREATING SPERM DNA FRAGMENTATION

It is possible to reduce sperm DNA fragmentation, in some cases, depending on the cause. Surgical repair of large varicoceles can improve DNA integrity as can treating infections with appropriate antibiotic therapy. Lifestyle measures that may be helpful include:

• Stay cool. Don’t soak in hot baths or hot tubs, avoid placing laptops over testes
• Stop smoking. Talk to your doctor about smoking cessation programs
• Lose weight. Obesity is linked to sperm DNA fragmentation
• Follow a healthful diet. Add a variety of fruits and vegetables rich in antioxidants to help combat oxidative stress
• Consider supplements. While many over-the-counter supplements for male fertility have not been proven effective, there are some supplements that may help reduce DNA fragmentation. These should be discussed with your doctor.