Are fluctuations in liver enzymes (e.g. alanine transaminase (ALT), aspartate transaminase (AST)) a normal occurrence during pregnancy?

From the Guidelines

Liver enzyme fluctuations, including mild elevations in ALT and AST, are considered a normal occurrence during pregnancy, particularly in the third trimester, as long as they remain below twice the upper limit of normal. These changes are attributed to the physiological stress of pregnancy, increased blood volume, and hormonal shifts that affect liver function 1. However, it is crucial to distinguish between normal physiological changes and potential pregnancy complications that may cause more substantial liver enzyme elevations, such as preeclampsia, HELLP syndrome, acute fatty liver of pregnancy, and intrahepatic cholestasis of pregnancy 1.

Key Considerations

• Mild elevations in liver enzymes are common and typically do not indicate underlying liver disease.
• Significant elevations (more than twice the upper limit of normal) warrant further investigation to rule out pregnancy-related liver conditions.
• Conditions like intrahepatic cholestasis of pregnancy (ICP) can cause elevated liver enzymes and require medical attention; ICP is characterized by generalized pruritus, elevated total bile acids, and sometimes elevated AST and ALT levels 1.
• Regular prenatal care includes monitoring liver enzyme levels to identify potential complications early.
• Symptoms such as severe nausea, vomiting, abdominal pain, itching, or jaundice accompanied by elevated liver enzymes should prompt immediate consultation with a healthcare provider.

Management and Monitoring

• For women with suspected ICP or other pregnancy-related liver conditions, monitoring should include regular checks of total bile acids and liver enzymes, with adjustments in management based on these values 1.
• The use of ursodeoxycholic acid (UDCA) may be considered for the treatment of ICP, as it has been shown to improve liver function tests and reduce the risk of premature birth and stillbirth 1.
• Women with a history of ICP or those at high risk should be considered for genetic screening to identify potential mutations in genes such as ABCB11, ABCB4, or ATP8B1, which are associated with an increased risk of ICP and possibly other liver diseases 1.

From the Research

Liver Enzyme Fluctuations During Pregnancy

• Fluctuations in liver enzymes, such as alanine transaminase (ALT) and aspartate transaminase (AST), can occur during pregnancy due to various physiological changes and potential liver diseases 2, 3, 4, 5, 6.
• These changes can be transient and rarely permanent, but disorders arising in pregnancy, such as pre-eclampsia and eclampsia, acute fatty liver of pregnancy (AFLP), and haemolysis, elevated liver enzyme and low platelets (HELLP) syndrome, can have serious implications 3, 4, 5.
• Abnormal liver function tests (LFTs) occur in 3-5% of pregnancies and can indicate potential severe liver injury, necessitating further assessment and accurate management 4.
• The interpretation of LFTs during pregnancy requires consideration of liver diseases specific to pregnancy and non-pregnancy-related liver damage, as well as pre-existing liver diseases 3, 4, 5.

Causes of Elevated Liver Enzymes

• The cause of elevated liver enzymes during pregnancy is unclear in up to 30-40% of cases, and little is known about the underlying mechanisms or association with maternal/fetal outcomes 2.
• Pregnancy-specific liver diseases, such as intrahepatic cholestasis of pregnancy, HELLP syndrome, and acute fatty liver of pregnancy, can result in fetal distress, severe liver damage, and sometimes hepatic failure 3, 4, 5.
• Physiological changes during pregnancy, including a hyperestrogenic state, increase in circulating plasma volume, and reduction in splanchnic vascular resistance, can mimic or worsen liver disease 2, 6.

Management and Diagnosis

• Proper interpretation of LFTs at an early stage can lead to timely management and reduce complications in both mother and fetus 3, 4, 5.
• A diagnostic work-up and management plan should consider liver diseases specific to pregnancy and non-pregnancy-related liver damage, as well as pre-existing liver diseases 2, 3, 4, 5, 6.
• A multi-disciplinary approach is necessary to mitigate maternal-fetal risks and manage liver disease in pregnancy 6.