What is sperm DNA damage and how can it affect male fertility?
Written by:Male factor infertility affects around 3 in 10 cases of infertility for couples trying to conceive. Trying for a baby can be a stressful process for couples, and it is important to find the reasons behind infertility problems. One such problem could be sperm DNA damage. Genetic integrity of sperm is absolutely crucial when it comes to successfully fertilising an embryo. Here, leading obstetrician and gynaecologist, Mr David Ogutu, explains sperm DNA damage, and how it can be treated in a fertility clinic like his.
What is sperm DNA damage?
Sperm DNA is vulnerable to damage. The main cause of the damage is oxidative stress (chemical damage caused by ‘oxidants’). Oxidants are derived from oxygen metabolism processes.
What is the significance of sperm DNA damage?
Sperm with DNA damage has reduced fertilisation potential, produces poorer quality embryos, and if implantation occurs, has a higher chance of miscarriage. There is also some evidence to suggest that men with high proportion of sperm with DNA damage produce offspring with a higher risk of autism and childhood cancers.
What causes sperm DNA damage?
Sperm DNA damage is very common. A study of 1600 infertile men in France showed that 60% had severe DNA damage. Men with abnormal sperm parameters, white blood cells in sperm, those exposed to harmful chemicals, those with febrile illness, varicocoeles, cancers and older men are more likely to have sperm DNA damage.
Eggs have a sperm DNA repair mechanism. However this mechanism is compromised with age, and contributes to the lower fertility rates seen in older women.
What happens if I have sperm DNA damage?
If you have abnormal sperm counts, or sperm DNA damage, then micro-injection of eggs into sperm for fertilisation (ICSI) is recommended. Using ICSI for fertilisation improves success rates if sperm has DNA damage.
Is there a test for sperm DNA damage?
There are tests available for sperm DNA damage. These will be performed on sperm before treatment. If a high proportion of sperm with DNA damage is found, then ICSI would be recommended for fertilisation.
Who should have the test?
Men with abnormal sperm counts will undergo ICSI anyway, so there is no clinical value in them taking a sperm DNA test. Those with normal sperm counts would benefit from the test, as it provides more information, to determine whether IVF or ICSI should be used for fertilisation.
Can sperm DNA damage be treated?
A recent research review has confirmed that ‘antioxidants’ (nutritional supplements with Vitamin C, E, zinc, selenium, carnitine and carotene) do reduce sperm DNA damage. The review of 23 research studies confirmed that taking anti oxidants reduces the proportion of sperm with DNA damage. Sperm motility also seems to improve. The review also confirmed a significant increase in clinical pregnancy rates with this treatment.
What does this mean for me?
We recommend that all men take antioxidants to start as soon as possible, and continue to take them during fertility treatment (ideally 2-3 months before fertilisation). These are cheap, and can be bought over the counter. It is also strongly recommended that women take fertility designed supplements.
If the sperm parameters are normal, taking a DNA test is recommended, as this will provide further information on how to proceed, i.e. review the need for ICSI vs. using IVF for fertilisation.
