ABNORMAL LIVER FUNCTION TESTS IN PREGNANCY

Screening tests for women presenting with abnormal liver function tests (LFTs) in pregnancy should include serology for hepatitis A, B, C, Epstein-Barr virus (EBV), cytomegalovirus (CMV) and herpes simplex virus (HSV) as well as an upper abdominal ultrasound to exclude biliary disorders.

Determine the stage of pregnancy, and whether there is anything in the history to indicate a liver disorder. A pregnancy-related liver disorder should be considered in the event of any relevant past history, or history of medications or in the presence of features of pre-eclampsia.

NORMAL PHYSIOLOGICAL CHANGES IN PREGNANCY

Normal physiological changes in pregnancy are shown in Table 48.1. The mother’s blood volume increases by 40%, and her total body water increases by 20%. This is reflected in a 10%–60% fall in serum albumin and also a fall in haemoglobin. Up to 50% of women develop spider naevi and palmar erythema during pregnancy, which is thought to be due to the increasing levels of oestrogen. This reverses quickly post delivery. Serum alkaline phosphatase increases 2–4-fold in the third trimester (placental) and gamma-glutamyltranspeptidase decreases slightly. No change is observed in the aminotransferases (alanine aminotransferase and aspartate aminotransferase) or the prothrombin time. A rise in the transaminases should lead to further investigation.

TABLE 48.1 Normal changes in liver function tests during pregnancy

Blood test	Change during pregnancy
Alkaline phosphatase	Increases 2–4-fold (placenta)
Gamma-glutamyl transpeptidase	No change or slightly decreases
Aspartate aminotransferase	No change
Alanine aminotransferase	No change
Bilirubin	No change or slightly increases
Bile salts	No change
Albumin	Decreases by 10%–60%
Globulin	Increases
Caeruloplasmin	Increases
Prothrombin time	No change
Cholesterol	2-fold increase
Triglycerides	2–3-fold increase

Up to 3% of pregnancies are complicated by abnormal LFTs at term. The best guide in determining the cause of abnormal LFTs is the timing of the problem during pregnancy (Figure 48.1). The differential diagnoses include:

• Liver diseases unique to pregnancy—generally occur in the third trimester (Table 48.2)

• Liver diseases occurring concomitantly—can occur anytime during pregnancy (Table 48.3)

• Preexisting chronic liver problems (Table 48.4).

FIGURE 48.1 Abnormal liver function tests in pregnancy.

TABLE 48.2 Liver diseases unique to pregnancy

TABLE 48.3 Liver disease occurring concomitantly during pregnancy

TABLE 48.4 Liver disease existing before pregnancy

Pregnancy is associated with an increased rate of gallstone formation. Hence cholecystitis and cholelithiasis need to be excluded in any pregnant woman presenting with right upper quadrant pain, nausea and abnormal LFTs. The differential diagnosis of right upper quadrant pain (Table 48.5) in late pregnancy includes pregnancy-related liver problems, such as liver involvement in pre-eclampsia, even hepatic infarction or rupture. It should be remembered that the gravid uterus pushes up the appendix, and appendicitis in late pregnancy can present with right upper quadrant pain.

TABLE 48.5 Differential diagnosis for right upper quadrant pain in the third trimester of pregnancy

Diagnosis	Incidence during pregnancy
Pyelonephritis	1%–2%
Cholelithiasis/cholecystitis	3%–5% have biliary sludge
Acute appendicitis	1/1500
Pancreatitis	1/1439
AFLP	1/10,000–1/15,000
Pre-eclampsia + liver involvement	<1%
HELLP syndrome	0.1%
Hepatic haematoma/rupture	1/45,000
Acute viral hepatitis	Same as in the general population
Acute Budd-Chiari syndrome	Rare