INTRODUCTION: In intrahepatic cholestasis of pregnancy (ICP), risk assessment rests on bile acid concentrations measured at diagnosis or at their peak. We asked whether a prespecified ≥50% decrease in total serum bile acids (TSBA) after ursodeoxycholic acid (UDCA) treatment predicts adverse perinatal outcomes.
METHODS: We retrospectively studied 200 singleton pregnancies with ICP (TSBA ≥19 µmol/L) treated with UDCA between January 2020 and January 2026. Women with a ≥50% decrease in TSBA at follow-up were classified as biochemical responders (n=135); the remainder were non-responders (n=65). The primary outcome was a composite of preterm birth, meconium-stained amniotic fluid, fetal distress, neonatal intensive care unit admission, or stillbirth. Logistic regression was adjusted for maternal age, body mass index, gestational age at diagnosis, and baseline TSBA.
RESULTS: The composite outcome occurred in 49.6% of responders and 69.2% of non-responders (adjusted odds ratio [aOR] 0.41, 95% confidence interval [CI] 0.21-0.80, p=0.009). The percentage decrease in TSBA discriminated the composite outcome better than baseline (area under the curve 0.613 versus 0.523) or peak TSBA (0.537, p<0.001). The group difference was confined to iatrogenic preterm birth (9.6% versus 29.2%, p<0.001); spontaneous preterm birth was similar, and a composite excluding iatrogenic preterm birth showed no association (aOR 0.87, p=0.659).
DISCUSSION AND CONCLUSION: The biochemical response to UDCA carries prognostic information beyond static bile acid values, but the association operates mainly through iatrogenic preterm delivery. Response assessment may support surveillance and counseling; it should not by itself trigger intervention.
Keywords: Intrahepatic cholestasis of pregnancy, Ursodeoxycholic acid, Bile acids, Premature birth, Pregnancy outcome