Does chlamydia infection cause miscarriage?

Sevi Giakoumelou, Andrew Horne, Sarah Howie, Gary Entrican

Previous research has suggested that chlamydia may increase risk of miscarriage, but the link has not been proven. Our researchers have been studying the link, and their work could provide the public with accurate health information about chlamydia and miscarriage.

Start: September 2012

End: December 2015

This project is now complete. 

Why do we need this research?

As many as 1 in 4 women will experience a miscarriage in their lifetime. For many of these women, there is no explanation for why it happened to them, or whether they could have another miscarriage in the future. We need to better understand the causes of miscarriage so that we can predict who is most at risk, and find ways to prevent it from happening.

Chlamydia is a sexually transmitted infection which in most cases does not cause any symptoms, meaning most people would be unaware if they are carriers. Previous research has suggested that there may be a link between miscarriage and the chlamydia. However, we don’t know enough to be certain, so more research is needed to confirm or disprove this link.

What happened in this project?

Researchers supported by Tommy’s have been investigating the link between chlamydia and miscarriage in different ways.

Firstly, our researchers studied in the lab how chlamydia affects cells from the lining of the womb. The attachment of the embryo to the womb lining, and the development of the placenta, is a complex process which involves many factors. Their research has shown that chlamydia infection might affect this process, meaning that placenta don’t work as they should.

Secondly, our researchers investigated if a chlamydia infection has any effect on pregnant mice. However, they found that chlamydia infection does not increase the rate of miscarriage in these mice.

Finally, our researchers are studying the link between chlamydia infection and miscarriage in women. They are currently recruiting 600 women, 300 who have had a miscarriage and 300 who haven’t, to determine if there is any difference in the rates of chlamydia infection. This could provide evidence whether or not chlamydia increases risk of miscarriage.

What difference will this project make?

The lab experiments in this project have shown that the link between chlamydia and miscarriage is not clear-cut. In their study with women, the researchers hope to show for certain whether or not there is a link. If it is found that chlamydia can cause miscarriage, it would mean that the public can receive accurate information about the risks of chlamydia, and could mean that screening is made more widely available.

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