Sperm DNA damage identified as New Biological Marker for recurrent miscarriages
Recurrent Pregnancy Loss (RPL) or Recurrent Miscarriages is defined as the consecutive losses of three or more pregnancies before 20 weeks of gestation.
Until very recently, miscarriages and recurrent pregnancy losses or RPL were always thought to be due to the female factor. However, many studies have been emphasising the role of the sperm DNA in causing miscarriages and Recurrent pregnancy losses.
In a recent article published in the Journal Clinical Chemistry by Dr. Channa N. Janasena, Senior Lecturer in Endocrinology, Department of Medicine, Imperial College, London says that the reason for Recurrent Pregnancy Loss (RPL) is the reduced sperm quality of the male partner of women who have undergone miscarriages.
Most often, doctors do many investigations on the female partner to determine the cause of miscarriage which could vary from presence of an infection or immune problems to blood and clotting factors, while neglecting to look into the contributory role of the male partner. But in recent years, it was been established that reduced sperm quality in male partners of women of RPL, and their reduced hormone levels are also contributory factors in recurrent miscarriages.
In this study, Dr. Janasena and his team investigated the sperm quality of 50 men whose partners suffered with RPL and compared the results with 60 male volunteers whose partners had no miscarriages. Results revealed that the sperm of those 50 men had higher levels of sperm DNA damage, when compared to the fertile control group. They reasoned that some of the possible causes for this high level of Sperm DNA fragmentation was due to the presence of reactive oxygen species (ROS) and reduced hormone levels. Hence they also compared the hormonal assays, semen ROS test and sperm DNA damage. There have been previous clinical studies by groups in Italy linking poor sperm DNA integrity to recurrent pregnancy loss and miscarriages as well.
Role of ROS and Hormone Levels in Men’s Fertility
Reactive Oxygen Species (ROS) are nothing but the scavenging antioxidant molecules present in the seminal fluid. When they are in optimal concentration, they help in the normal sperm function and acts as a protective barrier to the sperm cell preventing infection whereas in higher concentrations, it affects sperm parameters resulting in loss of sperm motility, decrease in sperm DNA integrity, decrease in the capacity of the oocyte-sperm fusion and eventually loss of fertility.
As discussed in our previous blog, hormones play a major role in the sperm production in men. The male hormone Testosterone is responsible for sperm production and the secondary sexual characteristics of the male accessory glands whereas estrogen plays a vital role in men’s sperm count.
This early stage study has shown some interesting findings:
Male patients from the RPL group had 15-16% lower hormone levels than their healthy counterparts. These RPL male partners also had upto 4 times the normal production of ROS in their semen when compared to the fertile group, increasing oxidative stress which we already know is one of the major causes of Sperm DNA Fragmentation.
The RPL group also presented with reduced sperm motility and morphology as well. The reasons behind higher ROS production in RPL group men were attributed to increased male age and overweight/ high BMI which is well known for increased ROS levels.
We at Andrology Center also have a done a small preliminary study with 167 patients reporting to a fertility centre who had mentioned miscarriage in their previous fertility history information.
Results showed that nearly 30% of these patients had poor sperm DNA integrity. This data further confirms the correlation between RPL/ Miscarriages and sperm DNA fragmentation.
Sperm DNA fragmentation can be used as a new biological marker for recurrent miscarriages in future.
It is studies like these that further strengthen the link between Sperm quality and recurrent miscarriages or recurrent pregnancy losses. Both patients and clinicians should be made aware that sperm DNA of this contributory factor when looking into various causes of recurrent miscarriages and recurrent pregnancy losses, where the male factor could also play a critical role. A standardised sperm DNA fragmentation test like the SCSA® Test will provide crucial information for the Clinician and patient to make a decision in further treatment management.
