Are Liver Function Tests (LFT) helpful in pregnant women without hypertension or pre-eclampsia?

Liver Function Tests in Pregnant Women Without Hypertension or Pre-eclampsia

Liver function tests are not routinely indicated in pregnant women without hypertension or pre-eclampsia, as abnormal liver tests occur in only 3-5% of pregnancies and are primarily associated with pregnancy-specific liver disorders or pre-existing conditions. 1, 2, 3

Normal Liver Function During Pregnancy

• Most liver function parameters remain within normal range throughout normal pregnancy 1:
  • ALT, AST, bilirubin, and gamma-glutamyltransferase remain normal
  • Alkaline phosphatase increases in 2nd and 3rd trimesters (placental origin)
  • Albumin may be normal or slightly decreased

When to Consider Liver Function Testing

Liver function tests should be performed in pregnant women without hypertension/pre-eclampsia when:

1. Symptoms suggestive of liver disease are present:

   • Nausea and vomiting beyond first trimester
   • Jaundice
   • Right upper quadrant pain
   • Pruritus (especially without rash)

2. Risk factors for pregnancy-specific liver disorders:

   • History of intrahepatic cholestasis in previous pregnancies
   • Multiple gestation
   • Family history of cholestasis

3. Pre-existing liver conditions:

   • Chronic viral hepatitis
   • Autoimmune hepatitis
   • Metabolic dysfunction-associated steatotic liver disease
   • Wilson's disease

Pregnancy-Specific Liver Disorders Not Associated with Hypertension/Pre-eclampsia

1. Hyperemesis Gravidarum:

   • Occurs in first trimester
   • 50% have liver dysfunction 2, 3
   • Presents with intractable vomiting and dehydration

2. Intrahepatic Cholestasis of Pregnancy:

   • Typically occurs in second half of pregnancy
   • Presents with pruritus and elevated bile acids
   • May have mild jaundice and elevated liver enzymes
   • Treatment: ursodeoxycholic acid
   • High risk for fetal complications 2, 3

Interpretation of Abnormal Liver Tests

When abnormal liver tests are found in pregnant women without hypertension/pre-eclampsia:

• Mild elevations in transaminases (ALT/AST <300 IU/L):

  • Consider viral hepatitis, medication effects, or early intrahepatic cholestasis

• Elevated bile acids with or without transaminase elevation:

  • Strongly suggests intrahepatic cholestasis of pregnancy

• Markedly elevated transaminases (>1000 IU/L):

  • Consider viral hepatitis or drug-induced liver injury

• Elevated bilirubin with normal or mildly elevated transaminases:

  • Consider hemolysis or Gilbert syndrome

Clinical Pitfalls to Avoid

1. Not recognizing early signs of pre-eclampsia: Liver dysfunction can precede hypertension in some cases of pre-eclampsia 1

2. Misattributing abnormal liver tests to normal pregnancy: Any elevation in transaminases, bilirubin, or bile acids is abnormal and requires investigation 1

3. Overlooking non-pregnancy-related causes: Viral hepatitis and gallstone disease are common coincidental causes of abnormal liver tests in pregnancy 3

4. Delaying diagnosis of intrahepatic cholestasis: This condition poses significant risks to the fetus despite relatively mild maternal symptoms 1

In conclusion, while routine liver function testing is not indicated in pregnant women without hypertension or pre-eclampsia, clinicians should maintain a low threshold for testing when symptoms or risk factors are present, as early diagnosis of liver disorders in pregnancy can significantly improve maternal and fetal outcomes.