What does more advanced sperm analysis involve pregnancy?
Further sperm tests are now available that are highly detailed. These are still controversial and as a result are not offered routinely, if at all, even in the majority of fertility clinics. You should check if your clinic offers tests for the following:
DNA fragmentation. This test is common in the USA but rarely available here. DNA is the genetic material carried on our chromosomes, and although the egg can still be fertilized by sperm that has some low-level poor sperm test results – there will be lots that can be done to help.
DNA damage, more serious damage means that either the sperm cannot fertilize the egg, or the resulting embryo is incompatible with life, and the pregnancy miscarries. Scientists can now screen sperm for DNA fragmentation or chromosomal abnormalities. Between 2 and 13 per cent of sperm are expected to be genetically abnormal, and although age can increase the figure, environmental and lifestyle factors, including cigarette smoking and alcohol, can also significantly affect the percentage of abnormal sperm. When DNA damage is not genetic in origin, it may be caused by free radicals in our diet and environment (55). But with a change in lifestyle, men can often reduce the amount of abnormal sperm and improve their fertility.
Aneuploidy. This occurs when there is one or more extra or missing chromosomes. This leads to genetic abnormalities, some of which are incompatible with life; others, such as trisomy 21 (or Down’s syndrome) will result in a fetal abnormality. There is an increased aneuploidy rate in sperm with fragmented DNA and there are two highly specialized tests that can determine this: a sperm chromatin dispersion (SCD) test and a fluorescence in situ hybridization (FISH) test.
P34H levels. Research has shown that the protein P34H plays a key role in fertilization and that low or nonexistent levels of the protein on the surface of sperm occur in a significant number of subfertile men. The protein is needed to enable fertilization to take place, so its low/ absent levels could throw light on certain cases of previously unexplained infertility. This is a new test and, although it is available in the US, it is currently available only in a few clinics in the UK.