Evaluating the Effect of Bile Acid Levels on Maternal and Perinatal Outcomes in Intrahepatic Cholestasis of Pregnancy: A Retrospective Study.

Background: Intrahepatic cholestasis of pregnancy (ICP) is the most common reversible liver disorder linked to pregnancy, characterised by pruritus and elevated serum bile acids (BAs). Condition severity correlates with increased maternal and neonatal complications, and recent evidence highlights a significantly elevated risk of adverse perinatal outcomes, including stillbirth, when BA > 100 µmol/L. Methods: This retrospective study, conducted at a tertiary perinatology centre between 2019 and 2023, was performed in two phases. In the first phase, baseline group characteristics and pregnancy outcomes were compared between ICP and non-ICP (control) groups. In the second phase, outcomes were analysed across three ICP severity subgroups: mild (BA < 40 µmol/L), moderate (BA 40-99 µmol/L), and severe (BA ≥ 100 µmol/L). Results: A total of 210 patients diagnosed with ICP and 24,177 controls were included in the analysis. After multivariable regression, the results indicated that patients with severe ICP (BA ≥ 100 µmol/L) experienced significantly worse perinatal outcomes compared to those with mild or moderate disease: spontaneous preterm birth occurred in 26.7% of cases (p = 0.002), iatrogenic preterm birth in 36.7% (p < 0.001), meconium-stained amniotic fluid in 43.3% (p = 0.001), and neonatal intensive care unit (NICU) admission in 23.3% (p = 0.006). This subgroup also had the lowest mean birth weight (2830 g, p < 0.001). Notably, no stillbirths were recorded in any of the subgroups. Compared to controls, no major differences in maternal characteristics were noted, except in pregnancies conceived via in vitro fertilisation (IVF, p = 0.012) and those complicated by gestational diabetes (p = 0.040), both showing elevated risk for ICP development. Conclusions: This study confirms an association between ICP and increased perinatal complications, with severity of disease correlating with poorer outcomes. The findings highlight the need for standardised BA testing and improved strategies for perinatal management.