The standard semen analysis is a great way to see if there are obvious problems with the man’s side of things as it checks sperm numbers, shape, pH and vitality, etc, and these are really important factors if enough sperm are going to physically make it to the ovaries to fertilise an egg. However what it doesn’t do is see if the sperm that get there “have what it takes” to create a viable pregnancy, and the results from a standard semen sample can be very similar for infertile and highly fertile men.
This is where the “additional sperm tests” come in, as they can check sperm quality and find hidden issues that prevent fertilisation or greatly increase the risks of miscarriage. For many couples they’re invaluable, as they provide a clear picture of the situation, stop them wasting valuable time, money and reduce heartache, which is often the hardest thing of all. They’re not tests that are usually considered until couples are having assisted reproductive techniques (ART) as most MD/GP’s rely on (or only know about) standard semen tests.
However some experts recommend that men in infertile couples have their DNA fragmentation checked “as routine” as it’s closely linked to lower fertilisation, embryo quality and pregnancy rates, as well as increased spontaneous miscarriage and childhood diseases.¹ All pregnancies involve some sort of risk, but it’s also possible to identify them and reduce them, which is what these tests can do.
We know about 40 sperm need to work together for one of them to actually manage to fertilise an egg, and not only do enough sperm need to reach an egg, once they’re there, they need to perform some important tasks:
- They need to physically break down the ‘zona’ (shell) around the egg for one sperm to penetrate and fertilize it. This involves both physical and chemical action by the head of the sperm and the enzymes carried in the ‘acrosome’
- The successful sperm must carry the correct DNA to create a healthy baby
- The genetic material on the DNA (the ‘program’ of information for the new life) needs to be relatively free from faults and be able to divide perfectly in the new cells²
- The sperm need to be free of anti-sperm antibodies as these can prevent sperm reaching an egg
If sperm can’t reach the egg, penetrate its shell and deliver viable DNA into it, the egg either won’t get fertilised, or the development of the embryo will be abnormal, and these are issues that affect both natural conception and IVF.
Additional semen tests are appropriate when:
[¹] ‘The impact of sperm DNA damage in assisted conception and beyond: recent advances in diagnosis and treatment.’ Lewis SE et.al. Reprod Biomed Online. 2013 Oct;27(4):325-37.
[²] Aitken RJ, De Iuliis GN and McLachlan RI (2009). Biological and clinical significance of DNA damage in the male germ line. Int J Androl 32(1):46-56