Can cholestasis of pregnancy cause elevated Lactate Dehydrogenase (LDH) levels?

Cholestasis of Pregnancy and LDH Levels

Intrahepatic cholestasis of pregnancy (ICP) is not typically associated with elevated lactate dehydrogenase (LDH) levels as part of its primary diagnostic criteria or laboratory profile. While ICP causes various liver function abnormalities, elevated LDH is not a characteristic feature of this condition.

Laboratory Profile in ICP

ICP is characterized by specific laboratory abnormalities:

• Primary diagnostic marker: Elevated serum bile acids ≥10 μmol/L 1, 2
• Common liver function abnormalities:
  • Elevated transaminases (ALT, AST) in most cases 2
  • Mild jaundice with moderately elevated conjugated bilirubin in only 10-15% of cases 2
  • Bilirubin typically <5 mg/dL 1

The laboratory evaluation table from the 2024 AGA Clinical Practice Update specifically outlines the expected laboratory findings in ICP and does not include elevated LDH as a characteristic feature 1.

Differential Diagnosis Considerations

When elevated LDH is found in pregnancy with liver dysfunction, other conditions should be considered:

1. HELLP syndrome: Characterized by hemolysis, elevated liver enzymes, and low platelets. Notably includes elevated LDH as a key laboratory finding 1.

2. Acute fatty liver of pregnancy (AFLP): May present with elevated LDH along with other markers of liver dysfunction 1.

The comparative table from the AGA guidelines clearly distinguishes these conditions 1:

Feature	ICP	HELLP	AFLP
Laboratory evaluation	Bilirubin <5 mg/dL, elevated bile acids	Bilirubin <5 mg/dL, hemolysis, low platelets, elevated LDH	Bilirubin <5 mg/dL, elevated ALP and GGT, hypoglycemia, elevated creatinine

Clinical Implications

If elevated LDH is found in a patient with suspected ICP:

• Consider alternative or concurrent diagnoses, particularly HELLP syndrome
• Evaluate for signs of hemolysis, which is associated with elevated LDH
• Monitor for complications such as preeclampsia, which is not typically associated with ICP but is seen in approximately 50% of AFLP cases and is characteristic of HELLP syndrome 1

Diagnostic Algorithm

When evaluating a pregnant patient with pruritus and abnormal liver tests:

1. Measure serum bile acids (primary diagnostic test for ICP)
2. Check liver function tests including ALT, AST, bilirubin
3. If LDH is elevated:
   • Evaluate for HELLP syndrome (check platelet count, evidence of hemolysis)
   • Evaluate for AFLP (check glucose, creatinine, coagulation studies)
   • Consider other causes of liver dysfunction in pregnancy

Conclusion

While ICP causes liver function abnormalities primarily characterized by elevated bile acids and transaminases, elevated LDH is not a typical feature of this condition. The presence of elevated LDH in a pregnant patient with liver dysfunction should prompt consideration of other pregnancy-related liver disorders, particularly HELLP syndrome or AFLP.