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Are sperm health and miscarriage linked?

Our resident fertility expert Dr Linda Farahani, explains her team’s latest research on the link between miscarriage and sperm health. 


Link between sperm health and miscarriage 

Our latest research at Imperial College , led by Dr Channa Jayasena, recommends that men should undergo tests when couples experience recurrent miscarriage. You might think this sounds obvious, however, historically when multiple pregnancies fail, the focus has very much been on the woman’s body. 

For this study, we tested 50 men whose partners had suffered recurrent miscarriages (defined as the loss of three consecutive pregnancies). We found that the sperm of the men in the miscarriage group had twice as much DNA damage as those in the control group. We think this could be caused by “reactive oxygen species” – molecules formed by cells in semen to protect sperm from bacterial and infection. In high enough concentrations, the molecules can cause significant damage to sperm cells. The men whose partners experienced miscarriage had four times more of the molecules compared to the control group. 


The bigger picture

This research adds to a growing body of research that sperm health matters. For a long time, science focussed on the role of the woman in fertility and pregnancy complications, largely driven by the fact that women have a biological cut off point for their fertility – the menopause. It is true that men don’t have the same “biological clock,” but recent research is starting to show that sperm health does decline with age and that the health of the sperm has an impact on pregnancy outcomes. 

One study found men over 40 years old were half as fertile as men under 25. Another study found it takes five times longer to conceive when the father is over 45. Previous research also suggests that sperm has an important role in the formation of the placenta, which is crucial for oxygen and nutrient supply to the body. 

The men whose partners had suffered miscarriage were older than the control group, with an average age of 37 compared to 30, and were slightly more overweight. Obesity can also cause fertility problems, and higher fat levels in the body could trigger an increase in reactive oxygen species. We are now investigating whether these factors may have affected the levels of reactive oxygen species. Although none of the men in the trial had any ongoing infection such as chlamydia, which we know can affect sperm health, it is possible there may be other bacteria from previous infections lingering in the prostate gland (which makes semen) – this could also lead to permanently high levels of reactive oxygen species. 

It is so important that we better understand the causes of miscarriage. Research from Dr Jessica Farren finds that women who have recently had a miscarriage are at risk of developing post-traumatic stress disorder. At our early pregnancy loss clinic, a third of the women have PTSD symptoms. If we understand miscarriage better, we can hopefully reduce the number of people who experience this trauma. 


Next steps

I’m excited to be leading the second phase of this study, where we’ll be seeking to investigate other aspects of sperm health that may be associated with miscarriage.  If you have experienced recurrent miscarriage, and are interested in taking part in this study please contact:

Dr Linda Farahani

Dr Channa Jayasena

Whatever the cause of fertility problems, it’s obviously crucial for no blame to be assigned. Instead we must have an open and honest conversation, empowering people to understand their health, putting in preventative measures where possible and providing people with right support. 

This is such important research, and I hope that by shedding light on the causes of miscarriage we can make steps towards reducing the number of miscarriages in the first place. 

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