Intrahepatic cholestasis of pregnancy (ICP) is a liver condition that can develop during gestation. This disorder affects the normal flow of bile, a digestive fluid. Instead of moving properly, bile acids can build up in the liver and spill into the bloodstream. This temporary condition typically resolves after birth.
Interpreting Positive Lab Results
ICP is diagnosed primarily by elevated total serum bile acid (TSBA) levels. A TSBA level greater than 10 µmol/L is generally considered diagnostic. Some guidelines suggest a higher threshold, such as 19 µmol/L or more, for a pregnancy-specific diagnosis.
Liver function tests, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), also aid diagnosis. Elevated levels of these enzymes, particularly ALT, can suggest liver cell damage and support an ICP diagnosis when combined with pruritus. These levels can increase significantly, sometimes 10 to 25 times the normal range.
While elevated bile acids are the most sensitive marker, liver enzyme levels are also indicative. Total bilirubin levels might be increased, though usually remaining below 5 mg/dL. Alkaline phosphatase (AP) also rises during pregnancy due to placental production, making it less useful for diagnosing cholestasis.
Recognizing Associated Symptoms
The most common symptom is intense itching, known as pruritus. This itching typically occurs without a rash and often becomes more noticeable on the palms of the hands and soles of the feet, though it can affect the entire body.
The itching tends to worsen at night, potentially disrupting sleep. While itching is common in pregnancy, the severity and presentation of ICP itching warrant medical evaluation. Some individuals may experience other, less common symptoms, including dark urine, pale stools, or yellowing of the skin and eyes, known as jaundice.
Potential Risks and Outcomes
Confirmed ICP carries potential risks for both the pregnant individual and the baby. For the pregnant person, there is a slightly increased risk of developing conditions like preeclampsia or gestational diabetes. Although rare with modern management, some may experience vitamin K deficiency, which can lead to bleeding issues.
For the baby, complications can be more concerning, especially as bile acid levels rise. Risks include preterm birth, which can occur in a significant percentage of cases, and meconium-stained amniotic fluid. Meconium passage is more common in ICP pregnancies, particularly with higher bile acid levels.
The most serious concern for the baby is stillbirth, a rare outcome. Its risk increases with higher maternal bile acid levels, especially when levels exceed 100 µmol/L. Stillbirths in ICP are thought to be related to irregular fetal heart rhythms or placental blood flow constriction caused by elevated bile acids.
Managing the Condition
Managing ICP involves monitoring and medical treatment. Frequent monitoring of bile acid levels and liver function tests tracks the condition’s progression. Fetal monitoring, such as non-stress tests or biophysical profiles, is also initiated, often around 32-34 weeks, to assess the baby’s well-being.
The primary medication used to treat ICP is Ursodeoxycholic Acid (UDCA). UDCA reduces bile acid concentration in the bloodstream, alleviating maternal itching. The typical dosage for UDCA ranges from 10 to 15 mg/kg per day, divided into two or three doses, and can be adjusted if symptoms persist.
Delivery timing is carefully considered based on bile acid levels and gestational age. For individuals with bile acid levels below 100 µmol/L, delivery may be considered between 36 and 39 weeks of gestation. If bile acid levels are 100 µmol/L or higher, delivery is often recommended around 36 weeks due to the increased risk of complications.