There has been an increase in the number of research articles exploring the male contribution to miscarriage. Given that a normal pregnancy is formed from both an egg and a sperm, it would be logical that the male partner must have some contributory role if miscarriage is the outcome of a pregnancy. If this is the case then there are several important questions we must consider.
- How does sperm contribute to miscarriage?
- How can sperm problems that contribute to miscarriage be identified?
- If there are sperm problems, can they be treated?
The impact of a woman’s age and egg health on pregnancy outcomes have been extensively studied. As women get older, they have a lower chance of natural conception and live birth from treatments such as IVF. Additionally, older women are known to have a higher chance of miscarriage. Older women are usually in relationships with older men whose contribution to these miscarriages may be of importance.
There is now growing evidence that a man’s age has an impact on sperm quality. There is a higher risk of stillbirth, birth defects, schizophrenia and autism in pregnancies and children of older men. Unlike women, who are born with as many eggs as they will ever have, men continue producing sperm from puberty until death. The sperm of older men have therefore undergone a lot of cell divisions and so there are higher chances of the sperm DNA having breaks in their structure. It is these sperm DNA breaks (or fragmentation) that has been suggested to cause problems with the pregnancy including miscarriage. The DNA of sperm is tightly wrapped around protein molecules and it seems to be more susceptible to damage as men grow older.
It has been suggested that measurement of sperm DNA fragmentation could be a useful way to identify men who contribute to a woman miscarrying a pregnancy. There are four main sperm DNA fragmentation tests and all four have very long names:
- SCSA – sperm chromatin structure assay
- TUNEL terminal deoxynucleotidyl transferase-mediated UTP nick-end labelling
- SCD sperm chromatin dispersion
Although there is good evidence that higher levels of sperm DNA fragmentation is linked with miscarriage, there is still a lot of research work to be done to define the best test to use. Additionally, there is lack of agreement on what level of sperm DNA fragmentation increases the risk of miscarriage. The lack of clarity surrounding DNA fragmentation means that the tests are not recommended in miscarriage guidelines. International guidelines suggest that the sperm DNA fragmentation tests can be used for explanatory reasons. However, the guidelines do not recommend that any treatments should be used to improve sperm DNA fragmentation. The treatments that have been put forward are mainly vitamins and antioxidants but latest trial data has not shown these treatments are of any benefit.
The research in to male contribution to miscarriage will continue to grow and it is likely that one day there will be a treatment for men to reduce the risks of miscarriage. For now though, what can men do to reduce the risk of miscarriage? Lifestyle is incredibly important – having a healthy balanced diet and ensuring regular exercise will ensure that sperm is as healthy as it can be to reduce the risks of miscarriage. Being at a healthy weight is likely to be of great benefit.
Finally, removing toxins such as cigarette smoke, alcohol and recreational drugs will be of benefit too. Male partners need to ensure they are doing all they can to try and optimise the outcome of any pregnancy they contribute to.