What is known about ICP

Research into the causes of ICP has been ongoing for over 30 years. However, researchers are still a long way from fully understanding the condition. Below is a brief summary of the key findings of ICP research.

Genetic variation

It has been shown that in some women there is variation in some genes responsible for the transport of molecules in the liver. These molecules are involved in the formation of bile, and when there is variation they work less efficiently. This means that there is a build up of bile acids in the blood, resulting in cholestasis. Although this has been a huge focus for research in ICP researchers are still a long way from explaining all cases by means of genetic variation and the work continues today.

Bile acids

A blood bile acid level of over 40 micromol/L at any time during a pregnancy appears to be associated with an increased risk of complications for your baby, including fetal distress and premature labour. It should be noted that the most recent large Swedish study measured fasting bile acid levels. In the UK, random blood samples are most commonly taken and the effect of food on bile acid level has not fully been established, although it is known that bile acids will rise after eating. More work is needed in this area to see if there is a similar correlation between random bile acid levels and risk to the baby.


There is some evidence that UDCA (ursodeoxycholic acid) treatment not only relieves the symptoms experienced by the mother, but may also offer some protection against the harmful effects of bile acids for the baby. These findings need to be confirmed in studies with larger numbers of women, and the mechanism established.

Bile acids and fetal complications

There are several ways in which bile acids may harm your baby. These include abnormal heart rhythms, abnormal contraction of the veins supplying your baby with nutrients, increased sensitivity of the uterus to hormones which may trigger labour, and increased sensitivity of the baby’s intestines to bile acids, which may cause passage of meconium. Again, more research is needed in this area as some pregnancies seem to be at higher risk than others.

Lysophosphatidic acid

Studies performed by a group in Amsterdam have shown that a phospholipid called LPA is likely to be the compound that causes itch. Future studies aim to establish the precise relationship between bile acids, LPA and severity of itch.