What is sperm DNA fragmentation and how does it affect your fertility?

by dee armstrong

Any couple who has been struggling to get pregnant for a while will be familiar with the various fertility tests that are usually offered. For her it's a blood test to check for ovulation, a hysterosalpinogram to check to see whether the fallopian tubes are clear and sometimes an AMH test to check her ovarian reserve. For him it's usually just a semen analysis.

The standard semen analysis has been around ever since IVF was invented and it hasn't been improved on since. There are quite a few things measured in the semen analysis but the main ones that couples will be familiar with are sperm count (the total number of sperm), motility (their swimming ability) and morphology (the shape and size of the sperm).

Actually, by 21st century standards, a semen analysis is a pretty crude test - it just looks at the outside of the sperm and tells you little about the intrinsic quality of the sperm DNA or its healthy baby-making abilities.  Certainly if a man's sperm count is very low, or they're not good swimmers, or if most of them have some abnormality (like two tails!) then, yes, that man's fertility is going to be compromised. But what about men whose semen analysis is OK but still their partner isn't getting pregnant naturally or by IVF? What about the couples who try round after round of IVF and are unsuccessful?  What about the couples who have repeated miscarriages?

Sperm DNA fragmentation might be the missing link and testing for it adds new information to help explain these situations.  It has been around as a research tool for 20 years, but it's only relatively recently that couples have been able to get the test done as part of their treatment.  When you get pregnant, the baby inherits some DNA from Mum and some from Dad.  Sometimes the DNA becomes damaged or fragmented - with strands breaking into smaller pieces.  Even healthy sperm may have some degree of DNA damage, as they can't repair themselves.  It's still being researched, but scientists think most damage is caused by the oxidative stress created by things like smoking, alcohol, environmental pollution, being overweight, and eating processed foods with poor nutrition.  Sometimes, if there is too much sperm DNA damage, that can prevent fertilisation taking place at all.  Amazingly, sometimes the egg is actually able to repair some of the sperm's DNA damage and fertilisation can take place. But when there is too much sperm DNA damage for the egg to repair, that can lead to the pregnancy stalling almost immediately, or you do get pregnant, but some time further down the line, suffer a miscarriage.

Professor Sheena Lewis, emeritus professor from Queen's University Belfast, is the UK's leading expert in sperm DNA fragmentation, and for 25 years she and her team have been working on new tests for the diagnosis of male infertility. They call the test the 'sperm comet' test because undamaged DNA bunches together and shines brightly, while damaged DNA fans out and glows weakly, looking like a celestial comet. The test is so sensitive that it detects damage in 80% of men with 'unexplained infertility', who seem to have normal semen by traditional tests.

I asked Professor Lewis why DNA damage was so important?

Sperm DNA damage is often a factor when couples have been trying for a baby for some time without success and where there is no obvious explanation why. It can also be a major factor where couples have been successful in conceiving, but have suffered a number of miscarriages. The important thing for men is to find out what their sperm quality is like. If we find there is a lot of sperm DNA damage, we can help couples make better choices about the right lifestyle choices and the best fertility treatment for them. For example, with moderate damage, IVF might be the best treatment to try first. If the damage is higher, then the best chance of success might be going straight to ICSI treatment.

If sperm can't repair themselves, what can men do?

Men are lucky.  Unlike women who have all their eggs at birth, men make a new batch of sperm every 3 months. If they test high for sperm DNA damage, they can take control by improving their lifestyle and DNA damage levels can decrease within within 3 -4 months.

A couple who consulted us at the Natural Fertility Centre recently had experienced 3 miscarriages in 18 months. They were feeling hopeless and had no idea that the man might be involved. Then they heard about DNA fragmentation. In this case, despite a relatively fit and healthy lifestyle, his DNA damage was high at 40%. He cleaned up his diet and started to take a  anti-oxidants from our NFC Essential range including coenzyme Q10, Vitamins C, D & E and bioflavonoids, amongst others. After 3 months his DNA fragmentation had reduced by 20% and they are now 7 months pregnant.  

Another couple had gone through 4 failed cycles of IVF.  They had never been told about DNA fragmentation and so spent £20,000 having treatment that was never likely to work.  They heard about sperm DNA testing and his test results came back with 56% DNA damage. He went on a lifestyle improvement regime, three months later had reduced the damage to 24% and the couple went on to have a successful cycle of IVF. 

Many of the couples I meet are relieved just to hear that there is more they can find out about why they are not getting (or staying) pregnant. Unfortunately, some doctors are still prone to telling men that there's nothing much they can do to improve their sperm. In fact, that's not the case at all. Getting good advice from an experienced nutritionist and supplementing with high quality antioxidants can make all the difference in the world.  In my view fertility specialists have also been slow to recommend the DNA fragmentation test to patients about to undergo assisted conception treatments. In the world of 'unexplained infertility' especially, it can make an enormous difference to find out that it's not unexplained at all and that information has to be a good thing.  

The spermcomet test can be booked at the Edinburgh branch of the Natural Fertility Centre - clinics are held on the last Sunday of each month. The test costs £450 and results are usually back within 7-10 days.  Get in touch with us if you have any other questions about it.