The Relationship Between Maternal Serum Afamin Levels and Intrahepatic Cholestasis of Pregnancy and Neonatal Outcomes

Objective: This study aimed to evaluate maternal serum afamin levels in women with intrahepatic cholestasis of pregnancy (ICP), examine their relationship with fasting bile acid concentrations, and assess their association with perinatal outcomes. Methods: This prospective case--control study included 80 singleton pregnancies followed at a tertiary perinatology center between October 2025 and March 2026. Forty women with ICP, defined by pruritus and fasting bile acids > 10 μmol/L, were compared with 40 healthy pregnant controls. Women with ICP were further stratified according to fasting bile acid levels as <40 and ≥40 μmol/L. Maternal serum afamin concentrations were measured using a commercially available enzyme-linked immunosorbent assay (ELISA) kit. Maternal characteristics, liver biochemistry, fetal biometric and Doppler parameters as well as obstetric and neonatal outcomes were compared. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of afamin for ICP, and logistic regression analysis was used to assess its association with ICP. Results: Baseline maternal characteristics were comparable between groups. Maternal serum afamin levels were significantly higher in the ICP group than in controls (6.18 ± 4.24 vs. 3.98 ± 1.95 ng/mL, p = 0.004). Afamin correlated positively with fasting bile acids (r = 0.372, p = 0.018), but not with transaminases, gestational age at delivery, birth weight, or neonatal outcomes. In logistic regression, afamin was independently associated with ICP (adjusted odds ratio [aOR] 1.260; 95% confidence interval [CI] 1.059-1.500; p = 0.009). ROC analysis showed poor discrimination for ICP (area under the curve [AUC] 0.634, 95% CI 0.51-0.76, p = 0.039), whereas afamin did not discriminate between subgroups defined by fasting bile acid levels (<40 vs. ≥40 μmol/L). The optimal cut-off value of 4.93 ng/mL predicted ICP with 55% sensitivity, 67.5% specificity, a positive likelihood ratio of 1.69, and a negative likelihood ratio of 0.67. Conclusions: Maternal serum afamin levels are elevated in ICP and show a modest association with fasting bile acid burden. Its discriminatory performance is limited, and it does not reliably distinguish patients defined by a ≥40 μmol/L threshold. These findings suggest that afamin reflects the maternal response to cholestasis rather than disease severity and may serve as a complementary biomarker.