Causes of male infertility
When we test sperm to see if it is normal or abnormal, here’s what we’re looking for:
Number and movement (aka concentration and motility)
A healthy ejaculate has over 40 million swimmers with at least half of them moving normally – in the right direction and at the right speed. If a man isn’t producing enough sperm, it significantly lowers the chance of conception.
Shape (aka morphology)
A healthy sperm has an oval head and a long tail to help it swim like a champion. Sperm with abnormally shaped heads or curled/double tails are less likely to fertilise an egg.
The genetic information (DNA) carried in the sperm head needs to be healthy. If there’s DNA damage, the embryo might not develop properly and there’s a risk of miscarriage. A regular turnover of sperm leads to less DNA damage, regular ejaculation is important so, in this case, thinking sexy thoughts can help.
Occasionally an ejaculation sample will be normal but the immune system – belonging to either the man or woman - makes anti-sperm antibodies which block the natural binding between sperm and eggs (doh) We can test for that too.
Other issues that can come up are:
Sometimes, sperm hit a proverbial brick wall on their way out of a man’s body. In this case, no sperm will be seen in a semen sample. Some men are born without the tubes (vas deferens) that carry sperm from the testicles while others might have a blockage because of an infection or surgery.
Absent sperm production
In some men, the amount of sperm produced by the testicles is so low that none appears in the ejaculation at all. This is commonly a genetic issue but sometimes we can find sperm using a minor surgical procedure on the testicles. That sperm can then be used in IVF to fertilise the partner’s eggs.
For many men the reason for changes to a normal sperm test cannot be explained. Some of the possible baby-making meddlers are genetic disorders, undescended testis, infections, heat, drugs or radiation damage are known to disrupt the production of healthy sperm. While some of these issues can be reversed, in many cases there are no treatments to correct poor sperm production so the man and his partner will need to have fertility treatment to achieve a pregnancy.