Most tests for male infertility, involve looking at the number, mobility and shape(morphology) of sperm. Although semen analysis tests may show sperm to be in the ‘normal’ range, they don’t take into account the quality of DNA within the sperm, which may be the cause of the infertility.

Sperm fragmentation is when the DNA within the sperm breaks. It can affect the chances of natural conception and conception through IVF. It has also been shown to be a factor in miscarriages too, as it is important for the normal development of the embryo.

It may be that sperm fragmentation accounts for many of the cases previously diagnosed as ‘unexplained infertility.’

What causes sperm fragmentation?

The damage to the DNA occurs either during sperm production or while the sperm is being stored in the body.

‘Breaks in the DNA strands are usually caused by oxidative stress. This produces free radicals that attack the DNA molecule. Sperm DNA fragmentation is therefore often associated with underlying medical conditions, or certain lifestyle choices including infection, varicocoele, smoking, alcohol, stress, poor diet, recreational drug use and advanced age (over 45years).’ Professor Sheena Lewis  


Is there a test for sperm fragmentation?

Sperm DNA damage testing in non-invasive, as it is performed on a semen sample, so there is no level of risk to the person having the test.

‘There is some evidence for a relationship between sperm DNA damage and the outcome of fertility treatment. However, the evidence is conflicting and depends on the type of test used by the clinic. The results of a sperm DNA damage test are unlikely to impact on the management of your treatment.’ (HFEA)

Can we still conceive, if my partner has sperm fragmentation?

Potentially, yes. You may have been struggling to conceive, or you may have had miscarriages that were possibly attributable to sperm fragmentation, but there are ways to help to create healthier sperm in the future. This can then lead to a greater chance of conception and birth.

As new sperm are continually being created, positive changes to diet and lifestyle can make a big difference in just a few months. If there is a varicocele present(enlarged veins within the scrotum) it may be able to be repaired, or treated with antibiotics. These changes mean that several months later, the new sperm that have been created, may not be fragmented.

ICSI (intracytoplasmic sperm injection) is a form of IVF used for men with weak or damaged sperm and can be more successful than traditional IVF.

Your doctor and fertility consultant will ask you lots of questions, about your medical history, diet and lifestyle, in order to build up a picture of what may be causing your infertility or miscarriages. From this, they will advise you on what course of action you can take moving forwards. You will also have the opportunity to ask them any questions regarding potential treatment.


Here at The IVF Network, we share a wealth of knowledge about fertility, conception and pregnancy. Through our dedicated channel of experts, our website and our blogposts, the information we provide, can help you to make more informed choices on your personal fertility journey.


‘Male infertility: sperm DNA fragmentation – the newest piece of the puzzle,’ Professor Sheena Lewis of Examen Laboratories IVF London

Male infertility: sperm DNA fragmentation


‘Sperm DNA damage’ HFEA (Human Fertilisation and Embryology Authority)