What are the diagnostic tests for suspected cholestasis (intrahepatic cholestasis of pregnancy) in pregnancy?

From the Guidelines

For suspected cholestasis in pregnancy, the recommended diagnostic tests include liver function tests, particularly serum bile acids, ALT, and AST, as recommended by the Society for Maternal-Fetal Medicine 1. The diagnosis of intrahepatic cholestasis of pregnancy is based on a serum bile acid level >10 mmol/L in the setting of pruritus, typically during the second or third trimester, as stated in the AGA clinical practice update on pregnancy-related gastrointestinal and liver disease 1. Key diagnostic tests include:

• Liver function tests (particularly serum bile acids, ALT, and AST)
• Complete blood count
• Coagulation studies
• Hepatitis serology
• Liver ultrasound
• Autoimmune markers to rule out other liver conditions Testing should be initiated promptly when a pregnant woman presents with pruritus, especially if it affects the palms and soles and worsens at night. Once diagnosed, weekly liver function tests and bile acid measurements are recommended to monitor disease progression, as suggested by the Society for Maternal-Fetal Medicine 1. Fetal surveillance with non-stress tests and ultrasounds for growth and amniotic fluid assessment should be performed regularly, with the goal of reducing the risks of preterm birth, fetal distress, and stillbirth associated with cholestasis of pregnancy, particularly when bile acid levels exceed 40 μmol/L, as noted in the AGA clinical practice update 1. Treatment typically involves ursodeoxycholic acid (10-15 mg/kg/day) to reduce maternal symptoms and potentially improve fetal outcomes, as recommended by the Society for Maternal-Fetal Medicine 1 and the AGA clinical practice update 1. Delivery is advised to be based on serum total bile acid levels, with the Society for Maternal-Fetal Medicine recommending delivery at 36 weeks or at diagnosis if after 36 weeks for levels >100 mmol/L, and delivery between 36 and 39 weeks of gestation for levels <100 mmol/L, as stated in their consult series #53 1.

From the Research

Diagnosis of Suspected Cholestasis in Pregnancy

• The diagnosis of intrahepatic cholestasis of pregnancy (ICP) is based on symptoms of pruritus, typically including the palms and soles, as well as elevated bile acid levels 2.
• Other liver function tests, such as alanine aminotransferase and aspartate aminotransferase, are also frequently elevated, and other causes of liver dysfunction should be ruled out 2.
• Fasting or non-fasting bile acids can be used to diagnose ICP, and disease severity can be classified based on bile acid levels 3.

Tests for Suspected Cholestasis

• Bile acid levels are a key diagnostic test for ICP, with levels ≥100 μmol/L associated with an increased risk of stillbirth 3.
• Liver function tests, such as alanine aminotransferase and aspartate aminotransferase, can also be used to support the diagnosis of ICP 2.
• Hepatobiliary ultrasound and viral serologies may not be necessary for routine screening, but can be used in cases of atypical clinical presentation or resistance to treatment 4.

Management of Suspected Cholestasis

• Ursodeoxycholic acid is commonly used to treat ICP, and has been shown to improve maternal pruritus symptoms and biochemical tests 2, 5, 6.
• Delivery may be considered at 37 weeks' gestation due to the increased risk of stillbirth associated with ICP 2, 5.
• Antenatal fetal wellbeing monitoring is also important in cases of suspected cholestasis, due to the increased risk of adverse perinatal outcomes 3.