Does cholestasis of pregnancy cause elevated Lactate Dehydrogenase (LDH)?

Intrahepatic Cholestasis of Pregnancy Does Not Cause Elevated LDH

Intrahepatic cholestasis of pregnancy (ICP) does not typically cause elevated lactate dehydrogenase (LDH) levels, as elevated LDH is not a characteristic laboratory finding in this condition. 1

Laboratory Findings in Intrahepatic Cholestasis of Pregnancy

ICP is characterized by specific laboratory abnormalities:

• Elevated serum bile acid levels (>11 μmol/L) - the most sensitive and specific marker for ICP diagnosis 1
• Elevated liver transaminases (ALT) usually <500 U/L 1
• Bilirubin typically <5 mg/dL, with mild jaundice occurring in only 10-15% of cases 1
• Normal LDH levels - LDH elevation is not listed as a characteristic laboratory finding in ICP in any major clinical guidelines 1

Differentiating ICP from Other Pregnancy-Related Liver Disorders

The 2024 AGA Clinical Practice Update clearly distinguishes the laboratory profiles of three major pregnancy-related liver disorders 1:

• Intrahepatic Cholestasis of Pregnancy (ICP): Characterized by elevated bile acids, mild to moderate ALT elevation, and bilirubin <5 mg/dL. LDH elevation is not listed as a characteristic feature. 1

• HELLP Syndrome: Specifically characterized by elevated LDH, hemolysis, low platelets (<100 × 10^9/L), and ALT <500 U/L. 1

• Acute Fatty Liver of Pregnancy (AFLP): Features hypoglycemia, elevated creatinine, prolonged PT, and DIC in >75% of cases. 1

Clinical Significance of LDH in Pregnancy-Related Disorders

• Elevated LDH is specifically associated with HELLP syndrome, where it serves as a marker of hemolysis and endothelial dysfunction 2
• LDH levels correlate with disease severity in preeclamptic and eclamptic women, but not in ICP 2
• When evaluating a pregnant woman with abnormal liver tests, the presence of elevated LDH should raise suspicion for HELLP syndrome rather than ICP 1

Diagnostic Approach to Liver Dysfunction in Pregnancy

When evaluating a pregnant woman with pruritus and suspected liver dysfunction:

• Measure serum bile acids and liver transaminases (ALT/AST) 1
• If bile acids are elevated (>11 μmol/L), especially with normal LDH, consider ICP 1
• If LDH is elevated along with low platelets and hemolysis, consider HELLP syndrome 1
• Bile acid levels may take time to rise; repeat testing is recommended if clinical suspicion remains high despite initial normal results 3

Management Implications

Understanding the laboratory profile of ICP is important because:

• ICP management focuses on maternal symptom control with ursodeoxycholic acid and timing of delivery based on bile acid levels 1
• Misdiagnosis of ICP as HELLP (or vice versa) could lead to inappropriate management decisions 1
• Bile acid levels >100 μmol/L warrant delivery at 36 weeks due to increased stillbirth risk 1
• For bile acid levels <100 μmol/L, delivery is recommended between 36-39 weeks 1

In summary, while ICP is characterized by elevated bile acids and liver transaminases, elevated LDH is not a typical feature of this condition and instead points toward HELLP syndrome or other pregnancy-related liver disorders.