Table 3. Expected laboratory variants of pregnancy important in the assessment of maternal liver disease195 .

Laboratory tests	Proposed reason for alteration
Elevated: Serum alkaline phosphatase Maternal serum alpha-fetoprotein 5' Nucleotidase Ceruloplasmin Serum cholesterol and triglycerides	Expected (2-4-fold) increase due to placental isoenzyme production Expected elevation due to placental production; can be elevated with fetal neural tube defects Expected mild elevation (trimesters 2 & 3) Expected elevation with pregnancy and estrogen exposure Expected elevations (trimester 2 with peak at term)
Normal: Aminotransferases (AST / ALT)* Serum total bile acid concentration* Prothrombin time	Expected to remain normal during pregnancy Expected to remain normal during pregnancy Expected to remain normal during pregnancy
Decreased: Serum albumin Total and unconjugated bilirubin* Conjugated bilirubin* Gamma-glutamyl transferase*	Expected decrease due to relative hemodilution (of red blood cell and hemoglobin mass) in the setting of greater plasma volume expansion (particularly in trimester 2) Expected decrease (all trimesters) Expected decrease (trimesters 2 & 3) Expected decrease (trimesters 2 & 3)

^*Abnormal (elevated) values may help to identify liver diseases in pregnancy, particularly in the setting of cholestasis.

Abbreviations: AST (aspartate aminotransferase); ALT (alanine aminotransferase).