Damage to sperm DNA could be a factor in recurrent miscarriages: study

A new study gives a glimmer of hope to couples with repeated miscarriages after investigating a possible new cause of the rare and relatively obscure disease – sperm abnormalities.

For couples seeking to expand their family, a miscarriage can be a traumatic experience. And for about one percent of those who try to have a baby, the horror repeats itself over and over again because of a condition known as Recurrent Pregnancy Loss, or RPL.

RPL is historically defined as the consecutive loss of at least three pregnancies before the twentieth week of gestation, although the European Society of Reproduction and Embryology has reduced the number of pregnancy failures to two in the guidelines updated last year.

In their quest to identify the underlying factors, researchers have traditionally focused on women with RPL and have isolated a number of medical problems that may contribute to spontaneous abortion. Chromosomal defects, uterine malformations, an incompetent cervix, diabetes, and autoimmune disorders all proved to be possible culprits.

However, most often, the cause remains a mystery. In fact, more than half of the cases are idiopathic, according to the British charity The Miscarriage Association, while the American College of Obstetricians and Gynecologists estimates that between 50 and 75% of cases remain unexplained .

Researchers at Imperial College London focused on paternal factors.

"We know that sperm play an important role in the formation of the placenta, which is essential for the survival of an unborn baby," said Channa Jayasena, principal investigator of the study presented at the meeting. Annual Meeting of the Endocrine Society in New Orleans this weekend. .

Jayasena and her team were interested in the sperm characteristics of male partners of women who had recurrent miscarriages, especially endocrine and metabolic sperm functions. They recruited 50 men whose partner had never suffered a pregnancy loss and 63 men whose partner was affected by the RPL for sperm badysis.

They evaluated the levels of reproductive hormones, including testosterone, and sperm count, motility and morphology, among other characteristics. The researchers also performed molecular tests to badess the levels of oxidative stress in sperm and damage to sperm DNA.

Oxidative stress is caused by a compound called reactive oxygen species (ROS). They are normally produced by the body, but when they are in excessive numbers, they damage the sperm and the DNA included in the sperm, which affects male fertility.

The researchers found that sperm ROS levels were four times higher in men with RPL than in their counterparts whose partners had never had a miscarriage, while the levels of spondyloarthropathy were significantly lower. DNA were twice as high as those of others.

"The male partners of women with RPL have reduced testosterone and serum estrogen concentrations compared to controls, which warrants further investigation.We also report a marked increase in the levels of ROS fragmentation and Sperm DNA and a reduction in the functional parameters of sperm compared to control participants, "the study read.

A miscarriage increases the risk of unsuccessful pregnancies by 14 to 21% after the first loss, by 24 to 29% after the second failure and by 31 to 33% following a third failure. And although six in ten women with RPL eventually have term pregnancy, estimates suggest that the unrealistic reasons for recurrent pregnancy loss hinder targeted therapies for couples seeking to conceive.

This study is the latest in a recent series of studies that examine the underlying causes of RPL outside the female body and examine the possible involvement of humans in the disease. The findings suggest a new approach to treating couples who have experienced recurrent miscarriages by examining male partners for potential reproductive problems and paving the way for more specific treatment plans.