The primary function of sperm is to carry the masculine DNA to the woman’s egg, and its quality as a transportation medium can be evaluated by means of a common semen analysis. However, a fragmentation test is required to analyze the quality of the DNA it transports, which is vitally important for the development of the embryo and the success of the pregnancy.
Some men with normal semen samples can have a high degree of DNA fragmentation, while others with very low sperm quality can have a minimum degree of fragmentation.
The DNA fragmentation test is recommended for couples that have not been able to conceive in spite of having been submitted to high complexity assisted reproduction treatments, for those who have suffered recurrent abortions or when the man suffers from uncontrolled chronic diseases such as diabetes.
The test is ideally performed before the first assisted reproduction treatment, because its results can help the couple and the fertility specialist to select the most adequate technique and prevent the physical, emotional, and financial stress of undergoing unsuccessful treatments.
Many cases of unexplained infertility are solved thanks to the DNA fragmentation test, during which the sperm is irrigated with a dye that only adheres to sperm with damaged DNA chains. The sperm are then passed one by one under a beam of light that illuminates the dye and makes them look orange (damaged) or green (normal). Finally, a computer counts the green and the orange sperm and calculates the DNA fragmentation index that is used to determine the degree to which the sperm have matured, and therefore their quality.
All men, whether fertile or infertile, have a percentage of sperm with fragmented DNA; however, a normal semen sample must have fewer than 15 percent of damaged sperm, while in serious cases of infertility these are more than 30 percent.
Among the factors that can cause DNA fragmentation are smoking, age (DNA fragmentation increases once the man reaches 45 years of age), seminal infections, testicular cancer, exposure to chemicals, contamination, drug use, oncological treatments such as chemotherapy or radiotherapy, among others. Prolonged exposure to heat in automobiles, saunas or hot tubs can also contribute to high sperm DNA fragmentation.
In some cases, the egg — as long as it is of good quality — is capable of repairing these lesions at the moment of fertilization. DNA fragmentation can also be treated with oral antioxidants for a period of 2 to 3 months, during which it is possible for it to be reduced up to 20 percent. However, it is possible for some patients not to respond to the treatment, especially when the damage to the DNA is induced by toxic factors or high temperatures.
In the situations in which the DNA fragmentation index cannot be improved, it is advisable to collect the sperm directly from the testicle by means of a biopsy and use them in an intracytoplasmic sperm injection (ICSI) procedure.
It has been seen that sperm extracted from the testicle have a significantly lower degree of fragmentation. This is because the genetic material of the sperm can be damaged by oxidation on its way from the testicle to the ejaculate.
We know at Ingenes that a correct diagnosis is the first step to obtain the adequate treatment, and therefore we have experienced personnel and state of the art equipment to perform the DNA fragmentation test at our facilities.