Intrahepatic cholestasis of pregnancy: detection with urinary bile acid assays

To determine sensitivity and specificity of urine bile acid sulfate (UBAS) and non-sulfated urine bile acid (UBA) assays for detection of intrahepatic cholestasis of pregnancy (ICP).

Urine was collected prospectively from healthy and pruritic patients evaluated for ICP. Results were expressed as a ratio to urinary creatinine.

Of 20 patients evaluated for ICP, 14 had confirmed ICP by serum testing and six had pruritus only. UBAS results were higher with ICP (P<0.001) and increased with gestational age in healthy controls. Adjusted for gestational age, the multiples of the median (MoM) were still higher (2.64+/-1.11, 1.05+/-0.54, P<0.001). The sensitivity was 100% and specificity 83% at 1.5 MoM in pruritic patients. UBA results were higher with ICP (23.0+/-9.8, 12.8+/-7.4, P<0.001), with sensitivity of 100% and specificity of 50% at 10.2 micromol/g cretinine.

Urinary bile acids can detect or exclude ICP with serum abnormalities. Urine bile acid sulfates have higher specificity than non-sulfated urine bile acids at equivalent sensitivities, but co-detection of progestin sulfates is suspected.