When should a pregnant woman worry about itchiness during pregnancy?

When Should a Pregnant Woman Worry About Itchiness?

A pregnant woman should worry about itchiness when it develops in the second half of pregnancy (especially after 28 weeks), particularly if it affects the palms and soles, worsens at night, and occurs without a visible rash—these features suggest intrahepatic cholestasis of pregnancy (ICP), which carries significant risk of stillbirth and requires immediate laboratory evaluation. 1

Red Flag Features Requiring Immediate Evaluation

High-Risk Presentation Characteristics

• New-onset pruritus without a rash developing in the second or third trimester should prompt immediate testing for ICP 1
• Itching predominantly affecting palms and soles that is worse at night is the classic presentation of ICP 1
• Generalized itching that is severe enough to disrupt sleep or cause excoriations from scratching 1
• Pruritus can occasionally present as early as the first trimester (occurs in approximately 5.6% of ICP cases), so early presentation should not exclude the diagnosis 2

Critical Laboratory Evaluation

When ICP is suspected based on clinical features, immediately order:

• Serum bile acid levels (most sensitive test; diagnostic when >10 μmol/L) 1, 3
• Liver transaminases (ALT and AST are elevated in most but not all cases) 1
• Bilirubin and gamma-glutamyl transferase (GGT) 1

Important caveat: Pruritus can precede laboratory abnormalities by several weeks 1. If initial bile acid levels are normal but symptoms persist and no other cause is identified, repeat testing is mandatory 1.

Risk Stratification Based on Bile Acid Levels

The severity of ICP and fetal risk correlates directly with bile acid levels:

• Bile acids ≥100 μmol/L: Substantially increased stillbirth risk requiring delivery at 36 0/7 weeks 3
• Bile acids <100 μmol/L but >40 μmol/L: Significantly increased fetal complication rates; delivery between 36 0/7 and 39 0/7 weeks 1, 3
• Bile acids >10 μmol/L but <40 μmol/L: Diagnostic of ICP; requires treatment and monitoring 1, 3

When NOT to Worry (Lower-Risk Presentations)

Benign Pruritus Features

• Pruritus with a visible rash (eczema, polymorphic eruption of pregnancy, or other dermatoses) is less likely to be ICP, though excoriations from scratching can be mistaken for a primary rash 1
• Pruritus affecting approximately 23% of pregnancies has no underlying pathologic process 3
• Itching that responds well to emollients and topical treatments without systemic features 4

Other Causes to Exclude

The differential diagnosis includes:

• Atopic dermatitis or eczema (usually with visible rash and history of atopy) 1
• Polymorphic eruption of pregnancy (PEP/PUPPP—presents with rash, typically on abdomen) 5, 6
• Pemphigoid gestationis (rare, presents with vesicles and bullae) 1, 5
• Pre-eclampsia and acute fatty liver of pregnancy (have other systemic features) 1
• Medication-related pruritus (particularly narcotics) 1

Management Algorithm Once ICP is Suspected

Immediate Actions

1. Order bile acids and liver function tests at first presentation of concerning pruritus 1, 3
2. Do not delay testing even if symptoms seem mild—stillbirth can occur suddenly without warning signs 1
3. Initiate ursodeoxycholic acid (UDCA) 10-15 mg/kg/day once diagnosis is confirmed (can be started empirically while awaiting results if clinical suspicion is high) 1, 3

Critical Pitfall to Avoid

Dark urine and jaundice are NOT commonly associated with ICP and should prompt evaluation for other hepatic diseases 1. Only 10-15% of ICP patients develop mild jaundice 1. The absence of jaundice should never reassure you against ICP if pruritus and elevated bile acids are present.

Rare but Important Presentations

• ICP can occur without itching (documented in 1.8% of cases), diagnosed incidentally on laboratory testing 2
• Excessive fatigue, insomnia, malaise, and abdominal pain are NOT typical of ICP; if present, evaluate for other causes of hepatic disease 1

Bottom Line for Clinical Practice

Any pregnant woman with new-onset itching in the second half of pregnancy without an obvious rash should have bile acids measured immediately 1, 3. The stakes are too high to miss this diagnosis—untreated ICP with elevated bile acids carries substantial stillbirth risk, particularly near term 1, 3. When in doubt, test. If bile acids are initially normal but symptoms persist, retest in 1-2 weeks 1.