Bile acids are compounds in the body that play a role in digestion. While normally present and necessary, their levels can become elevated during pregnancy, potentially leading to specific health considerations. Understanding bile acids in pregnancy is important for expectant parents.
Understanding Bile Acids
Bile acids are compounds produced in the liver from cholesterol, then stored and concentrated in the gallbladder. Their primary function is aiding the digestion and absorption of dietary fats and fat-soluble vitamins. When food enters the digestive system, the gallbladder releases bile, rich in these acids, into the small intestine.
These acids act as natural detergents, breaking down large fat globules into smaller particles. This process, called emulsification, allows digestive enzymes to work more effectively on fats. Bile acids also help eliminate excess cholesterol and waste products from the body. After completing their digestive work, most bile acids are reabsorbed in the small intestine and returned to the liver for reuse, a cycle known as enterohepatic circulation.
Bile Acids and Pregnancy
During pregnancy, particularly in later stages, bile acid levels can rise due to pregnancy hormones like estrogen and progesterone. These hormones can affect the liver’s ability to transport bile, reducing its flow from the liver. When bile flow slows, bile acids can build up in the liver and enter the bloodstream.
This condition is Intrahepatic Cholestasis of Pregnancy (ICP), also known as Obstetric Cholestasis. It is a liver disorder specific to pregnancy, where impaired bile flow leads to bile acid accumulation. The exact cause is complex, but it involves hormonal, genetic, and environmental factors. ICP is the most common liver condition occurring during pregnancy.
Recognizing High Bile Acid Levels
The primary symptom of elevated bile acids in pregnancy is intense itching, known as pruritus. This itching often lacks a rash and commonly affects the palms of the hands and soles of the feet, though it can occur anywhere on the body. It frequently worsens at night, potentially disrupting sleep.
Less common symptoms include dark urine or pale stools, though these are not always present. If a pregnant individual experiences persistent unexplained itching, especially in the second or third trimester, healthcare providers will consider an ICP diagnosis. Diagnosis is confirmed through a blood test measuring serum bile acid levels. A total serum bile acid level greater than 10 µmol/L indicates ICP, even if other liver function tests are normal.
Addressing High Bile Acid Levels
Management strategies for elevated bile acids in pregnancy focus on reducing bile acid levels, alleviating maternal symptoms, and improving outcomes for the developing baby. The primary medication used is ursodeoxycholic acid (UDCA), often prescribed as Ursodiol. UDCA works by improving liver function, enhancing bile flow, and reducing bile acid concentration in the bloodstream.
Treatment with UDCA begins as soon as ICP is diagnosed and continues until delivery. Healthcare providers conduct close monitoring of both the pregnant individual and the fetus. This includes regular blood tests to track bile acid levels and liver function, every one to two weeks. Fetal surveillance, such as non-stress tests, is increased, particularly after 34 weeks of gestation, to assess fetal well-being.
Post-Delivery Considerations
Following childbirth, bile acid levels return to normal, and itching symptoms resolve rapidly. This occurs as pregnancy hormones, which contributed to the condition, subside after delivery. It is recommended that individuals have their liver function and bile acid levels retested around six to twelve weeks postpartum to confirm ICP resolution and rule out any underlying liver conditions.
For individuals who have experienced ICP, there is a possibility of recurrence in future pregnancies, with estimates ranging from 60% to 90%. While ICP is temporary and resolves after birth, the baby’s well-being is closely monitored during pregnancy and post-delivery, as elevated bile acids can pose risks such as preterm birth or respiratory issues.