Conclusions

In our study we demonstrated that a normal pregnancy is a sub-cholestatic state and is associated with physiological elevation of TSBA levels compared to non-pregnant adults. By defining pregnancy-specific reference ranges, we can avoid unnecessary diagnosis of ICP that is strongly correlated with maternal anxiety and active management.
We recommend that higher threshold should be used for the diagnosis of ICP. We suggest using the upper limit in the normal pregnant population: fasting TSBA values ≥14 µmol/L and postprandial TSBA values ≥20 µmol/L. We also suggest both values should be measured, as each provide different information: the fasting measurement is more specific for the diagnosis and the postprandial is essential for risk stratification and severity assessment. Since TSBA values usually increase after food intake, the measurement should not be random, as two different thresholds should be used for the fasting and postprandial measurements.