Interpretation
The finding of elevated bile acids in a pregnant patient is suggestive of intrahepatic cholestasis of pregnancy (ICP) (also known as obstetric cholestasis (OC)), particularly if the LFTs are otherwise largely unremarkable and the patient has symptoms of ICP (e.g. itching). This is a non-specific finding however, as bile acids may also be elevated in other liver disorders.
The Society of Obstetric Medicine of Australia and New Zealand recommends that a non-fasting total serum bile acids (TSBA) is used to diagnose ICP. ICP is diagnosed if the TSBA is ≥19μmol/L in a pregnant woman with pruritus and in the absence of pre-existing liver diseas. Severe and very severe ICP are diagnosed if the TSBA is ≥40μmol/L and ≥100μmol/L respectively.
Gross elevations of plasma bile acids may be associated with adverse foetal outcomes although the data on this relationship is unclear. Bile acids results may be contribute towards management decisions in pregnancy, but it is not recommended that decisions are made from the TSBA result alone.
ICP is often treated with ursodeoxycholic acid (UDCA) which is itself a bile acid. Monitoring of serum bile acids in a patient on UDCA may present a challenge as the assay will recognise the UDCA which can lead to spuriously high results. If the patient is on UDCA, it is recommended to collect a trough (pre-dose) bile acids level to minimise the impact of the drug on the result.
Reference Intervals
| Total serum bile acids (TSBA) |
Diagnosis |
| ≥19 μmol/L |
Intrahepatic cholestasis of pregnancy (ICP) |
| ≥40μmol/L |
Severe ICP |
| ≥100μmol/L |
Very severe ICP |
Note: ICP criteria should only be used in pregnant women with itching and with no other pre-existing liver disease
Test Method
Performed on Beckman Coulter AU5822 analyser using Sentinel Reagents.
