What is DNA fragmentation and how is it tested?

The latest advances in assisted conception suggest that we need to measure men’s fertility more accurately

A basic semen analysis is just skimming the surface of what is really going on inside the sperm. With more information about the inner workings of the sperm we can explore those factors relating to a man’s lifestyle and health which could be reducing sperm health and therefore fertility.

That gives us a chance to ‘put things right’ often before treatment has even started and improve the chances of any treatment working. Measuring the levels of DNA fragmentation in sperm is a current area of research interest which appears to be shedding quite a bit of light on why so many couples end up with a diagnosis of ‘unexplained infertility’, failed IVF, or miscarriage despite the egg health and sperm health initially appearing to be good.

Recent advances in medical diagnostics has allowed us to get a much more detailed window into the health of sperm, which links to the health of the embryo.

The conventional male test is a semen analysis measures, along with the count, the sperm morphology (shape) and movement characteristics, but now we can also measure the level of sperm DNA damage, or fragmentation.

This test measures the integrity of the DNA inside the head of the sperm and is reported as the DNA Fragility Index (DFI)

In a DNA fragmentation test, a sample of ejaculated sperm is sent off to measure its DNA Fragility Index (DFI) using a diagnostic technique called flow cytometry. High DFI levels reflect more genetic damage in sperm and therefore lower sperm health.

DFI levels greater than 15% have been linked to unexplained fertility, lower success rates in all assisted conception treatment cycles and, in some studies, an increased risk of miscarriage.

All men should expect to have a certain level of damage to their sperm DNA but recent data show that more than 20% of males with otherwise good sperm parameters show DNA damage above the normal values of 15%.

DNA damage can be caused by increased oxidative stress in the testicular compartment which, in turn, can be triggered by a number of factors including exposure to toxic substances such as nicotine, alcohol or recreational drugs, obesity, medical illnesses including the common cold or ‘flu, infection and excess heat.

All cells in the body suffer some DNA damage through oxidative stress but self repair mechanisms aren’t always able to repair this damage.

The best approach to improve DFI levels is to look for the possible causes, try to remove them and wait for new sperm to be formed which takes around 3 months.

How is it treated?

It all depends on the cause. The Fertility Consultant should first explore the man’s lifestyle as stopping smoking, alcohol, caffeine, body building drugs or recreational drugs can significantly improve DFI levels as can taking antioxidants (male vitamin supplements).

We advise that all men with elevated DFI consider an infection screen on the urine and sperm as if an infection is identified, antibiotics can be prescribed to the man and in some cases the couple to help reduce the DFI levels. It is also sensible in some cases for the man to be examined by a male fertility expert as a varicocoele, which is when there is abnormal dilatation of the veins in the scrotum, can cause elevate DFI levels.

At the Agora we offer an enhanced male fertility MOT

This measures the level of DNA fragmentation, levels of reactive oxidative stress, looks for the presence of infection in both the semen and urine and finally looks at sperm binding which is a measure of how well the sperm may bind to the egg.

The main focus if the results are abnormal is to find the cause and put a plan of treatment or life-style changes into place if any of the results. We usually expect an improvement within three months which is the normal sperm-cycle.

When the results are abnormal and have not been improved with treatment, we usually advise ICSI and other measures during the treatment cycle to reduce the negative effect of high levels of DNA damage on pregnancy outcome.