Introduction:
The aim of this study is to compare first- and second-trimester Down syndrome biochemical screening markers in intrahepatic cholestasis of pregnancy (ICP) and normal pregnancies.

Material and methods:
This observational case-control study was conducted at Health Sciences University Zeynep Kamil Maternity and Children’s Health Training and Research Hospital and the Department of Obstetrics and Gynecology at Erciyes University Medical Faculty during 2016–2017. The study included 165 patients, and consisted of 62 women who had been diagnosed with ICP (the ICP-diagnosed group) and 103 healthy pregnant women (the control group). First-trimester free β-human chorionic gonadotropin (β-hCG), pregnancy-associated plasma protein-A (PAPP-A) and second-trimester total β-hCG, estriol (E3), -fetoprotein (AFP), and inhibin A levels were compared between the two groups.

Results:
The mean patient age was 28.67 ±5.96 years, with no significant difference between the groups (p > 0.05). Average PAPP-A levels were significantly lower in the ICP-diagnosed group (p < 0.001). When the cut-off value for PAPP-A was taken as ≤ 0.93 multiple of median (MoM), the sensitivity and specificity values for ICP were 73.8% and 56.3%, respectively (95% CI, AUC ± SE: 0.663 ±0.042).

Conclusions:
The decrease in PAPP-A MoM value indicates an increase in the risk of developing ICP, while changes in other markers were not sufficient to predict ICP.