What impact does ‘mild’ ICP have on the baby?

Tommy’s researchers want to find out what the risks are in intrahepatic cholestasis pregnancies with lower levels of bile acids.
  • Authors list

    Professor Catherine Williamson, Professor Lucy Chappell

This project took place at our London centre which operated between 1995 and 2021. 

Intrahepatic cholestasis of pregnancy (ICP), also known as obstetric cholestasis (OC), is a liver disorder that can develop during pregnancy. It affects around 1 in 140 pregnancies in the UK. 

ICP is caused by a raised level of bile acids in the liver, which then leak into the woman’s bloodstream. It is characterised by itching skin, which is often more noticeable on the palms of the hands and soles of the feet. 

ICP can have serious consequences for the baby, with increased chances of premature birth, neonatal unit admission and stillbirth. Research shows that about 1 in 10 women diagnosed with ICP will have their baby early. 

The normal bile acid level in the blood is below 10-14 µmol/L. When it rises above this concentration ICP is diagnosed. A Swedish study in 2004 demonstrated that higher bile acid levels (above 40 µmol/L) are associated with worse outcomes for the baby. Since then, ICP is diagnosed as ‘mild’ or ‘severe’ based upon whether bile acids are below or above 40 µmol/L. 

We know that the higher the bile acid levels, the worse the outcome is for the baby, but we don’t yet know what the impact is on the baby of having lower bile acids. 

This study aims to find out whether babies of ‘mild’ ICP pregnancies are also at increased risk. And at what level of bile acids does this risk occur. 

We also want to determine the best course of care for women with lower bile acids. 

To do this, we are collecting data from all published studies into ICP. We are currently compiling the results to see if there is a bile acid level above which women are more at risk. We are also looking at individual patient data from ICP studies. So far, we have collected data from over 3000 women from 13 different countries. 

We hope that this study will provide conclusive evidence upon which to base our care of affected women in the future.

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This project is funded by Tommy's and ICP Support.