Researchers uncover link between damaged sperm and miscarriage
What role does sperm quality play in the risk of miscarriage?? © Sashkinw/ thinkstock
Poor sperm quality: contrary to popular belief, the causes of recurrent miscarriages do not appear to lie solely in the health of the mother. As a study now suggests, the father also plays a role. According to the study, the sperm cells of affected men show a conspicuous amount of DNA damage. This could be caused by the accumulation of highly reactive oxygen molecules and possibly be a consequence of bacterial infections or aging processes.
If expectant parents lose their child before the fetus would have been able to survive with the help of intensive medical support, doctors speak of a miscarriage. This event, also called miscarriage, is psychologically very stressful for affected couples – especially if it happens more than once.
Such recurrent miscarriages are usually associated with health problems of the mother. It is known, for example, that infections or immune diseases increase the risk of an early termination of pregnancy. But recently it is emerging that the father can also influence the risk of miscarriage.
Conspicuous DNA damage
"According to recent studies, male sperm plays an important role in, among other things, the formation of the placenta, which is crucial for supplying oxygen and nutrients to the unborn baby," says Channa Jayasena of Imperial College London. For this reason, he and his colleagues have now investigated the possible role of the father in this context in more detail.
For their study, the scientists compared the sperm of 50 men whose wives had already suffered a miscarriage at least three times with the sperm of 60 test subjects whose partners had not yet experienced an abortion. This actually revealed a conspicuous feature: the sperm of the men affected by miscarriages showed numerous DNA damages – twice as many as the sperm of the test subjects from the control group.
Result of infections?
Jayasena’s team attributes this damage to the influence of so-called reactive oxygen species (ROS). The concentration of these highly reactive molecules was increased fourfold in the affected men. Among other things, ROS are formed in the body’s cells in the course of defense against bacterial infections – but if they get out of hand, this can be harmful.
"While none of the subjects suffered from a bacterial infection – for example, with chlamydia – at the time of the examination. However, germs from previous infections may still remain in the prostate gland. This could lead to permanently elevated concentrations of reactive oxygen species in the sperm cells," suspects Jayasena.
Reducing the risk of miscarriage
In addition, influencing factors such as obesity and the age of the men could also play a role. The analyses showed that the men whose wives had suffered repeated miscarriages were on average seven years older than the test subjects from the control group and also weighed in with slightly more excess pounds. "We are now investigating whether these factors may have also affected ROS levels," the team writes.
"If further studies confirm that reactive oxygen species in sperm affect miscarriage risk, we may be able to develop therapies that reduce the concentration of these molecules and increase the chance of a healthy pregnancy," Jayasena concludes. (Clinical Chemistry, 2019; doi: clinchem.2018.289348)