Elevated Sperm DNA Fragmentation
DNA is the genetic information contained in all cells, including sperm. Intact sperm DNA is necessary for normal egg fertilization. Sperm that has DNA with breaks in the strands is abnormal, and is called “DNA fragmentation”. This may cause sperm to function poorly and is not measured by the standard semen analysis. Therefore, testing for DNA breaks or fragmentation may be helpful to identify a male factor problem in some cases. The threshold for an abnormal DNA fragmentation is generally considered to be 30%.
Overall, there is an association between high levels of DNA fragmentation and reduced fertility.
Elevated sperm DNA fragmentation has been associated with:
- Lower natural pregnancy rates
- Lower pregnancy rates with Intrauterine Insemination (IUI)
- Lower pregnancy rates with In Vitro Fertilization (IVF)
- Higher miscarriage rates
Conditions resulting in increased sperm DNA fragmentation include:
- Excessive alcohol
- Fever or infection
- Testicular trauma
- Varicocele or other anatomic abnormalities
- Environmental chemicals or radiation
- Advanced paternal age
- Cancer and its treatments
These are men in whom we may consider DNA fragmentation testing. DNA fragmentation testing may also be considered in men with prolonged infertility of unknown origin, poor outcomes after assisted reproductive technologies (such as poor fertilization or poor embryo development) and recurrent miscarriages.
Strategies to decrease sperm DNA fragmentation levels may include:
- Antioxidant supplementation
- Lifestyle modifications
- Varicocele repair
- Testicular sperm extraction
For some men, DNA damage occurs as sperm travel through the epididymis. Accordingly, the use of sperm obtained directly from the testicle for Intracytoplasmic Sperm Injection (ICSI) has been shown to result in improved live birth rates, among other fertility parameters. We believe that extracting testicular sperm provides healthier sperm to be used at ICSI. Because of this (after optimization of all other lifestyle factors), elevated sperm DNA fragmentation is generally treated with ICSI and Testicular Sperm Extraction (TESE).