The role of gut bacteria in intrahepatic cholestasis of pregnancy

Our researchers have made discoveries about how the bacteria in our gut changes during pregnancy. This could lead to new ways to treat health complications and help all women have a healthy pregnancy.
  • Author's list

    Dr Caroline Ovadia, Cyrus Fan, Prof Catherine Williamson, Dr Peter Dixon

This project is now complete.

Why do we need this research?

Pregnancy causes changes in the metabolism which are important to help the baby grow, but can sometimes lead to complications such as intrahepatic cholestasis of pregnancy (ICP). We need to better understand the causes of conditions like ICP, so that we can find new ways to diagnose and treat them and protect the health of mother and baby.

What happened in this project?

Researchers supported by Tommy’s investigated the link between the ‘friendly’ gut bacteria and our metabolism, and how these change during pregnancy. In particular, they studied the effects of bacteria on chemicals called bile acids. These substances are produced by our liver and help us digest fat in our diet.

Our researchers found that a type of bacteria called Bacteroidetes increases in number during pregnancy. These bacteria break down bile acids and prevent them from being absorbed by the gut, which leads to more bile acids being produced by the liver. Our researchers think that this is important for the developing baby. However, abnormally high levels of bile acids in the blood can sometimes lead to ICP.

Tommy’s researchers then went on to study what effect a drug called UDCA, used to treat ICP, has on the bacteria in the gut. UDCA helps to increase the numbers of Bacteroidetes bacteria in the gut, which can break down bile acids. Interestingly, UDCA itself is modified by bacteria, which eventually leads to the liver producing fewer bile acids. These results might explain how UDCA improves the symptoms of ICP.

What difference will this project make?

This research has improved our understanding of how the bacteria in our gut changes during pregnancy, and how this might contribute to intrahepatic cholestasis of pregnancy (ICP). Our researchers have also learnt more about how UDCA helps to treat ICP. This work has led to our researchers setting up the GUARD trial, to test using UDCA to treat another complication of pregnancy, gestational diabetes. Ultimately, this work will help us treat pregnancy complications and help more women have a healthy birth.

Thanks for your interest in our research

Tommy's funds research across the UK investigating the reasons for miscarriage, stillbirth and premature birth. We can keep you updated on ways you can support our work. If you would like to join our fight against baby loss and premature birth, click here.