The goal of this observational study is to learn if analyzing bile acid patterns can help predict dangerous complications in pregnant women with intrahepatic cholestasis of pregnancy (ICP), a liver condition that can affect the baby. The main questions it aims to answer are:

• Can measuring specific types of bile acids (particularly taurine-conjugated versus glycine-conjugated bile acids) in the mother's and baby's blood help predict the risk of stillbirth and other complications?
• Do these bile acid patterns activate specific receptors (TGR5) that might contribute to immune problems or heart rhythm abnormalities in the baby?
• How do bile acid patterns in the mother's stool relate to her gut bacteria and the severity of ICP?
• Can heart rate monitoring (CTG) combined with bile acid measurements better identify high-risk pregnancies? ICP is a pregnancy-related liver condition that causes bile acids to build up in the mother's bloodstream. This can lead to serious risks for the baby, including an increased chance of stillbirth, premature birth, and heart rhythm problems. Current monitoring methods (such as heart rate monitoring and ultrasound) often don't show warning signs before complications occur.

Participants will:

• Provide blood samples at each routine bile acid check during pregnancy and at delivery
• Provide stool samples for analyzing gut bacteria and bile acids
• Have their baby's umbilical cord blood collected at birth for bile acid analysis
• Undergo standard heart rate monitoring (CTG) of the baby
• Have ultrasound examination of the baby's heart (echocardiography) The study will compare three groups: pregnant women with ICP, healthy pregnant women, and healthy non-pregnant women. The researchers hope this information will help doctors better predict which pregnancies need more intensive monitoring and potentially prevent stillbirths and other complications in women with ICP.

Inclusion Criteria Group I:

• Minimum age of 18 years
• Written informed consent
• Pregnant patients with suspected ICP
• Pregnant patients with confirmed ICP
• Pregnant patients with elevated total bile acids (>14 µmol/ml)
• Pregnant patients with elevated liver enzymes
• Pregnant patients that suffer from itching with elevated transaminases

Inclusion Criteria Group II:

• Minimum age of 18 years
• Confirmed pregnancy
• Written informed consent
• Generally considered healthy in common usage (corresponding to ASA II of the American Society of Anesthesiologists classification)

Inclusion Criteria Group III:

• Minimum age of 18 years
• Female gender
• Pregnancy excluded
• Written informed consent
• Generally considered healthy in common usage (corresponding to ASA II of the American Society of Anesthesiologists classification)

Exclusion Criteria Group II and III:

• Age <18 years
• Inability to provide informed consent
• Signs of an acute illness (for control groups II and III)
• Known liver, biliary, or pancreatic diseases (for control groups II and III)
• ICP in personal or family medical history (for control groups II and III)

Group 1:

Participants in this group are pregnant women diagnosed with or suspected of having ICP who are being treated at the Clinic for Obstetrics, University Hospital Jena, as part of routine clinical care.

Group 2:

Participants in this group are healthy pregnant women without ICP who are receiving routine prenatal care at the Clinic for Obstetrics, University Hospital Jena.

Group 3:

Participants in this group are healthy, non-pregnant female volunteers participating in the study independently of the clinical care setting.

• The data concerns a vulnerable population (pregnant individuals and their newborns), which is why personal information is treated with particular sensitivity.
• The local data protection policy must be observed.
• In scientific cooperation, a release is conceivable after careful review and in accordance with legal, ethical, and organizational requirements.