Identifying DNA Fragmentation

Times Are Changing

From the early days of sperm testing until relatively recently, male fertility testing did not change much. Evaluation of the semen was performed, for many years, by a laboratory technician looking through a microscope and manually counting sperm. The determination of sperm motility, what constituted fast moving sperm from sperm with medium motility to slow movement, was completely arbitrary. The results depended upon the technicians and they often came up with very different numbers when it came to counts or motility.

There's More Than Movement Involved Here

Also, the common belief among most reproductive specialists was that if a man's sperm was live, then they were suitable to use for IVF or intracytoplasmic sperm injection (ICSI). If the female partner did not conceive or miscarried, then it was determined that the problem was with the egg, not the sperm. Studies indicated that measurement of the normal parameters of routine sperm analysis had no bearing upon the success of ICSI. Many couples, after failed IVF attempts, sought egg donation as an alternative since the husband's semen testing was normal and conception hadn't happened. Even at that, some couples failed to conceive with "good donor eggs", leaving all parties in the equation concerned and confused. Some couples opted to go on from there to surrogate birth using an egg donor and also came up barren. The only common denominator was the husband's sperm.

Discovering Damaged DNA

Very recently a new concept was introduced to the practice of assisted reproduction and male fertility testing. It was determined that sperm quality was not tied to numbers, but rather to the amount of damage to sperm DNA. This is called DNA fragmentation. When the DNA in the sperm is faulty, it won't function properly and it was discovered that sperm DNA fragmentation has little or nothing to do with the original way of determining sperm validity through routine semen analysis. Men with a high sperm count can have a large amount of DNA damage and men with a low sperm count can have very little DNA damage. What is really important is the finding that the amount of DNA fragmentation definitely affects the ability of the sperm to penetrate and initiate pregnancy regardless whether IVF, ICSI or another type of technology is used.

Sperm that has a high amount of DNA fragmentation may fertilize an egg but embryo development stops before the egg is implanted, or a pregnancy may occur but there is a significantly higher risk of miscarriage. Through the DNA fragmentation testing of sperm, many cases of unexplained infertility now have an identifiable cause.

Testing For DNA Fragmentation

There are different tests which can be used to determine DNA fragmentation. However, the one that has received the most attention is the SCSA, or sperm chromatin structure analysis, wherein the sperm are treated with a dye which, very simply, identifies damaged DNA in sperm. Through the use of special equipment to differentiate the sperm and a computer program to graph the sperm, the doctor can determine the amount of DNA fragmentation present. This information may help to identify whether a man has an infertility problem and whether it can then be treated.