What causes postpartum itching?

Causes of Postpartum Itching

Postpartum itching that persists beyond 4-6 weeks after delivery indicates underlying chronic liver disease and requires immediate evaluation, as intrahepatic cholestasis of pregnancy (ICP) should completely resolve within this timeframe. 1

Primary Cause During Pregnancy: Intrahepatic Cholestasis of Pregnancy

ICP is the most important pathological cause of itching during pregnancy, characterized by intense pruritus, elevated serum bile acids (>10 μmol/L), and elevated liver transaminases. 1 This condition affects 0.4%-10% of pregnancies depending on geography and ethnicity, with highest rates among Latina women (up to 5.6% in the United States). 2

Pathophysiology of ICP

The underlying mechanisms involve multiple factors:

• Genetic mutations in hepatic phospholipid transporter (ABCB4), bile salt export pump (ABCB11), and ATP8B1 explain familial clustering and ethnic predisposition. 2
• Hormonal factors play a central role, evidenced by higher incidence in twin pregnancies and triggering by high-dose oral contraceptives and progesterone. 1
• Maternal risk factors include advanced maternal age, multiparity, metabolic syndrome, and HCV infection. 2

Clinical Presentation

The classic symptom is generalized pruritus most severe in palms and soles without an accompanying rash, typically presenting in the second or third trimester (80% after 30 weeks gestation). 2 AST and ALT levels may be elevated 2-fold to 30-fold higher than normal. 2

Expected Postpartum Resolution

Pruritus and elevated bile acids should completely resolve within 4-6 weeks postpartum, and liver function tests should normalize during this same timeframe. 1 The condition spontaneously resolves after delivery in the vast majority of cases. 1

Causes of Persistent Postpartum Itching (Beyond 6 Weeks)

Pruritus persisting beyond 6 weeks postpartum suggests underlying chronic liver disease and requires comprehensive evaluation. 1 The differential diagnosis includes:

Chronic Hepatobiliary Conditions

• Primary biliary cholangitis (PBC) - autoimmune destruction of intrahepatic bile ducts 1
• Primary sclerosing cholangitis (PSC) - chronic cholestatic liver disease 1
• ABCB4 deficiency - genetic bile transport disorder 1
• Chronic hepatitis C - viral hepatitis with cholestatic features 1

Genetic Variants

Women with genetic variants in ABCB11, ABCB4, or ATP8B1 have a different risk profile and may develop:

• Benign recurrent intrahepatic cholestasis 2
• Progressive familial intrahepatic cholestasis 2
• Progressive liver disease, gallstones, cholangitis, and possibly liver cancer 2

Genetic testing should be considered in women with severe ICP (total bile acids >100 μmol), recurrent ICP, or early-onset ICP. 2

Diagnostic Evaluation for Persistent Postpartum Itching

When itching persists beyond 6 weeks postpartum, the following workup is essential:

• Serum bile acids - should have normalized; persistent elevation indicates ongoing cholestasis 1
• ALT, AST, bilirubin, GGT - assess for hepatocellular versus cholestatic pattern 1
• Prothrombin time - monitor for vitamin K deficiency from cholestasis 1
• Autoimmune markers - antimitochondrial antibodies for PBC, ANCA for PSC 1
• Viral hepatitis serologies - if not previously tested 1

Management of Persistent Postpartum Cholestasis

Ursodeoxycholic acid (UDCA) is safe in pregnancy and lactation and should be continued postpartum for primary biliary cholangitis. 1 Additional management includes:

• Cholestyramine for bile acid sequestration 1
• Rifampin for refractory pruritus 1
• S-adenosyl-L-methionine as adjunctive therapy 1
• Antihistamines for symptomatic relief 1

Monitor prothrombin time regularly due to vitamin K deficiency risk from cholestasis, particularly if using cholestyramine. 1

Other Pregnancy-Related Dermatoses (Not True Postpartum Causes)

While these conditions cause itching during pregnancy, they typically resolve postpartum:

Atopic Eruption of Pregnancy (AEP)

The most common dermatosis of pregnancy, affecting approximately 23% of pregnancies, presenting with pruritus and visible eczematous rash. 3, 4 This is benign and resolves postpartum. 5

Polymorphic Eruption of Pregnancy (PEP/PUPPP)

The second most common pregnancy-specific dermatosis, characterized by pruritic urticarial papules and plaques on the abdomen and proximal thighs. 3, 6 Rash regression is usually observed within 6 weeks postpartum. 6

Pemphigoid Gestationis (PG)

A rare itching bullous disease of pregnancy and the postpartum period that can persist after delivery. 7 This autoimmune condition may require continued treatment postpartum. 7

Critical Pitfalls to Avoid

• Never assume ICP has resolved if symptoms persist beyond 6 weeks postpartum, as this indicates underlying chronic liver disease requiring workup. 1
• Do not miss vitamin K deficiency in patients with persistent cholestasis, especially those on cholestyramine, as this can lead to hemorrhage. 1
• Recognize that up to 90% recurrence risk exists in subsequent pregnancies for women who had ICP. 1
• Persistent abnormal liver tests after delivery warrant reconsideration of chronic hepatobiliary conditions. 1

Recurrence Risk and Future Pregnancies

Recurrent ICP is reported in 40%-92% of women with a personal history of ICP. 2 Family history is significant, as familial clustering suggests genetic susceptibility requiring counseling for future pregnancies. 1