Perinatology logo

Alanine Aminotransferase (ALT, SGPT) — Pregnancy Reference Values

Perinatology.com › Reference › Serum › ALT (SGPT)

Alanine aminotransferase (ALT, SGPT) — serum

ALT levels in healthy pregnancy are typically normal or slightly lower than in nonpregnant adults. Any elevation above pregnancy-specific upper limits should be interpreted in clinical context, especially when accompanied by symptoms, hypertension, jaundice, or other abnormal liver tests.

Units Nonpregnant Adult 1st Trimester 2nd Trimester 3rd Trimester
U/L 7 – 41 3 – 30 2 – 33 2 – 25
µkat/L 0.12 – 0.68 0.05 – 0.50 0.03 – 0.55 0.03 – 0.42
Causes of elevated ALT
  • Pregnancy-related liver disorders
    • HELLP syndrome
    • Acute fatty liver of pregnancy (AFLP)
    • Preeclampsia with liver involvement
    • Intrahepatic cholestasis of pregnancy (ICP)
    • Hyperemesis gravidarum
  • Hepatocellular injury
    • Viral hepatitis (A, B, C, E; EBV, CMV, HSV)
    • Drug-induced liver injury (acetaminophen, antiepileptics, isoniazid, methyldopa, antibiotics, herbal agents)
    • Alcohol-associated liver disease
    • NAFLD / NASH
    • Autoimmune hepatitis
    • Ischemic hepatitis (“shock liver”)
  • Cholestatic or biliary disease
    • Choledocholithiasis, cholecystitis, cholangitis
    • Extrahepatic bile duct obstruction
    • PBC or PSC (less common)
  • Metabolic / genetic / chronic liver diseases
    • Wilson disease
    • Hemochromatosis
    • Alpha-1 antitrypsin deficiency
    • Chronic hepatitis syndromes

Very high ALT (>500–1000 U/L) most commonly indicates viral hepatitis, acetaminophen toxicity, or ischemic hepatitis. Moderate elevations (2–20× ULN) are common in HELLP, AFLP, ICP, and hyperemesis gravidarum.

Causes of low or low-normal ALT
  • Normal physiologic variation
    • Low ALT is common and usually not pathologic
    • Hemodilution of pregnancy may slightly lower measured ALT
  • Nutritional or metabolic
    • Vitamin B6 (pyridoxine) deficiency
    • Severe malnutrition or cachexia
  • Advanced chronic liver disease
    • End-stage cirrhosis can produce low ALT due to reduced hepatocyte mass
  • Pregnancy-specific interpretation
    • Isolated low ALT in healthy pregnancy is almost always benign
    • Concern should focus on ALT elevation with symptoms or abnormal labs

References

  1. Abbassi-Ghanavati M, Greer LG, Cunningham FG. Pregnancy and laboratory studies: a reference table for clinicians. Obstet Gynecol. 2009;114:1326–31.
  2. Wallach J. Interpretation of Diagnostic Tests, 8th ed.
  3. Fischbach FT, Dunning MB. A Manual of Laboratory and Diagnostic Tests, 7th ed.