# Intrahepatic Cholestasis of Pregnancy

## Overview

### Definition

Intrahepatic cholestasis of pregnancy (ICP) is a liver disorder unique to pregnancy characterized by pruritus and elevated serum bile acids. It is the most common pregnancy-specific liver disease and typically presents in the second or third trimester, usually after 30 weeks, though earlier onset can occur. ICP resolves spontaneously after delivery.

### Epidemiology

The incidence ranges from 0.2 to 2% of pregnancies in North America and Europe, rising to 5 to 15% in Chile and Bolivia. It is more common in women of South American (particularly Araucanian Indian), Scandinavian, and South Asian descent, with a higher prevalence during winter months. The recurrence rate in subsequent pregnancies is 60 to 70%. Risk factors include twin or multiple gestation, IVF conception, advanced maternal age, hepatitis C infection, family history of ICP, and prior ICP.

### Pathophysiology

The underlying mechanism involves impaired bile acid secretion across the hepatocyte canalicular membrane. Estrogen and progesterone metabolites inhibit hepatocellular bile acid transporters, particularly BSEP (ABCB11). Genetic susceptibility plays a role, with variants identified in the bile salt export pump gene and other hepatobiliary transporter genes including MDR3 (ABCB4). Elevated maternal bile acids cross the placenta and accumulate in fetal circulation, where they may cause placental vasoconstriction, cardiomyocyte dysfunction, and meconium-stained amniotic fluid.

## Clinical Presentation

### Symptoms

Pruritus is the hallmark symptom and typically begins on the palms and soles before generalizing. It characteristically worsens at night and can be severe and debilitating. Importantly, there is no primary skin rash -- any excoriations present are secondary to scratching. In some cases, pruritus precedes laboratory abnormalities by days to weeks. Associated symptoms include insomnia, fatigue, and depression from the severity of itching. Pale stools and dark urine are less common findings. Steatorrhea and fat-soluble vitamin malabsorption can occur in severe cases. Jaundice is absent in most patients, occurring in fewer than 25%; when present, it suggests severe disease.

### Physical Exam

Examination reveals excoriations on the extremities and trunk from scratching. Mild hepatomegaly may be present. There are no stigmata of chronic liver disease, and no rash other than scratch marks is found.

## Diagnosis

### Serum Bile Acids

A total serum bile acid level of 10 micromol/L or greater is the diagnostic threshold in the appropriate clinical context. Fasting levels are preferred because postprandial levels are higher and may be falsely elevated. Bile acid levels can lag behind symptom onset, so if the initial level is normal and symptoms persist, testing should be repeated in 1 to 2 weeks. Cholic acid and chenodeoxycholic acid are the predominant elevated bile acids.

### Risk Stratification by Bile Acid Level

ICP severity is stratified by bile acid concentration. Mild ICP is defined by bile acids of 10 to 39 micromol/L. Moderate ICP corresponds to levels of 40 to 99 micromol/L. Severe ICP is defined as bile acids of 100 micromol/L or greater, which carries the strongest association with adverse fetal outcomes. The landmark meta-analysis by Ovadia et al. in 2019 demonstrated that stillbirth risk is significantly elevated above the 100 micromol/L threshold.

| ICP Severity | Bile Acid Level | Stillbirth Risk | Recommended Delivery |
|---|---|---|---|
| Mild | 10-39 micromol/L | Not significantly elevated | 36+0 to 39+0 weeks |
| Moderate | 40-99 micromol/L | Modestly elevated | 36+0 to 37+0 weeks |
| Severe | ≥100 micromol/L | Significantly elevated | 34+0 to 36+0 weeks |

### Other Laboratory Findings

Transaminases are elevated in 20 to 60% of cases, with AST and ALT rising to 2 to 10 times normal. Gamma-glutamyl transferase (GGT) is characteristically normal or only mildly elevated, in contrast to biliary obstruction where GGT is prominently elevated. Bilirubin is normal or mildly elevated, with a direct fraction if elevation is present. PT/INR is usually normal but may be prolonged from vitamin K deficiency due to fat malabsorption. CBC, hepatitis serologies, and liver ultrasound are obtained to exclude other causes of liver disease.

### Differential Diagnosis

The differential includes preeclampsia and HELLP syndrome (assessed by platelet count, creatinine, and blood pressure), acute fatty liver of pregnancy (distinguished by hypoglycemia, coagulopathy, and renal failure), viral hepatitis (A, B, C, E), biliary obstruction from cholelithiasis, primary biliary cholangitis (evaluated with antimitochondrial antibodies if suspected), drug-induced liver injury, and dermatologic causes of pruritus including PUPPP, pemphigoid gestationis, and eczema.

<image>Diagnostic algorithm for intrahepatic cholestasis of pregnancy, starting with pruritus without primary rash, branching through bile acid measurement, liver function tests, exclusion of other hepatic and dermatologic conditions, and risk stratification by bile acid level</image>

## Management

### Ursodeoxycholic Acid (UDCA)

UDCA is the first-line treatment, dosed at 10 to 15 mg/kg/day divided into 2 to 3 doses (typically 300 mg twice or three times daily). It works by displacing toxic hydrophobic bile acids, improving bile flow, and protecting hepatocytes. UDCA provides symptomatic relief, reducing pruritus in 67 to 80% of patients within 1 to 2 weeks, and lowers bile acid and transaminase levels. The question of fetal benefit remains debated. The PITCHES trial in 2019 found that UDCA did not significantly reduce a composite adverse perinatal outcome, though the trial was underpowered for stillbirth as an endpoint. Despite this uncertainty regarding fetal benefit, UDCA remains widely used for symptom relief and is well tolerated with minimal side effects (mild diarrhea).

### Adjunctive Symptomatic Treatment

Antihistamines such as diphenhydramine and hydroxyzine provide sedative effects helpful for nighttime pruritus but have no effect on bile acid levels. Emollients and cool compresses offer additional comfort. Cholestyramine, a bile acid sequestrant, has limited efficacy and is poorly tolerated due to gastrointestinal side effects; it may also worsen fat-soluble vitamin deficiency. Rifampin is reserved for refractory cases and enhances bile acid metabolism, though liver function tests must be monitored for potential hepatotoxicity. S-adenosylmethionine (SAMe) has limited evidence and is used primarily in some European centers. Dexamethasone is not recommended due to insufficient evidence and potential harms.

### Monitoring

Serial bile acid levels every 1 to 2 weeks guide risk stratification and delivery timing. Weekly liver function tests are monitored until stable. Coagulation parameters (PT/INR) are checked in severe cases, with vitamin K administered if prolongation is found. Fetal surveillance with nonstress testing or biophysical profile begins at 32 to 36 weeks depending on institutional practice, with more frequent testing for severe ICP.

<image>Graph showing the relationship between total serum bile acid levels (x-axis) and relative risk of stillbirth (y-axis), demonstrating the exponential increase in stillbirth risk above 100 micromol/L, with threshold markers at 40 and 100 micromol/L</image>

## Fetal Risks

### Adverse Outcomes

Stillbirth is the primary concern and is associated with bile acid levels of 100 micromol/L or greater. The Ovadia et al. 2019 meta-analysis found no significantly increased stillbirth risk below the 100 micromol/L threshold. The mechanism of fetal death is thought to involve sudden fetal cardiac arrhythmia or acute placental vasoconstriction mediated by bile acids, and stillbirth may occur without warning and is often not preceded by abnormal fetal testing. Spontaneous preterm labor occurs in 20 to 40% of ICP cases. Meconium-stained amniotic fluid is 2 to 3 times more common because bile acids stimulate fetal colonic motility. Fetal distress during labor and neonatal respiratory distress (possibly related to meconium or bile acid effects on surfactant) are additional concerns.

### Limitations of Antenatal Testing

Standard antenatal testing with NST and BPP may not predict sudden fetal death in ICP. The mechanism of stillbirth is thought to be an acute event (bile acid-induced arrhythmia) rather than gradual hypoxia, which is what standard testing is designed to detect. This unpredictability is the primary driver of the practice of early delivery.

## Delivery Timing

### Current Recommendations (Risk-Stratified)

For mild ICP (bile acids 10 to 39 micromol/L), delivery is recommended at 36 weeks 0 days to 39 weeks 0 days, with many institutions delivering at 37 weeks. For moderate ICP (bile acids 40 to 99 micromol/L), delivery is recommended at 36 weeks 0 days to 37 weeks 0 days. For severe ICP (bile acids 100 micromol/L or greater), delivery is recommended at 34 weeks 0 days to 36 weeks 0 days, with antenatal corticosteroids administered if delivery is planned before 37 weeks. Earlier delivery is indicated for worsening liver function, coagulopathy, or non-reassuring fetal status.

### Mode of Delivery

Vaginal delivery is preferred, as ICP is not an indication for cesarean delivery. Continuous fetal monitoring is used during labor because meconium and fetal distress are more common. Amniotomy should be performed to assess for meconium.

## Postpartum Course

Pruritus typically resolves within 24 to 48 hours of delivery, and bile acids and liver function tests normalize within 2 to 8 weeks postpartum. If symptoms or laboratory abnormalities persist beyond 6 to 8 weeks, investigation for underlying chronic liver disease is warranted. Bile acids and liver function tests should be rechecked at 6 to 8 weeks postpartum to confirm resolution. Regarding contraception, estrogen-containing contraceptives may trigger recurrence and should be used with caution; progestin-only methods are preferable.

## Recurrence and Counseling

The recurrence rate is 60 to 70% in subsequent pregnancies, and recurrence may occur at an earlier gestational age and with greater severity. ICP may also recur with use of estrogen-containing oral contraceptives. Patients should be counseled to report symptoms early in future pregnancies. There are no long-term hepatic sequelae outside of pregnancy in the absence of an underlying genetic cholestatic disorder.

## Clinical Pearls

ICP presents with pruritus, especially of the palms and soles, without a primary rash. Any rash present is from scratching.

A normal bile acid level does not rule out ICP if symptoms are present. Testing should be repeated in 1 to 2 weeks.

The critical bile acid threshold for markedly increased stillbirth risk is 100 micromol/L or greater, as established by the Ovadia et al. meta-analysis.

Antenatal testing may not predict sudden fetal death in ICP. The mechanism of stillbirth is likely acute cardiac arrhythmia rather than gradual hypoxia.

UDCA effectively relieves pruritus, but fetal survival benefit remains unproven based on the PITCHES trial.

ICP does not cause long-term liver disease. If laboratory values do not normalize postpartum, further investigation is needed.

Always check PT/INR in severe ICP and administer vitamin K before delivery if prolonged, as there is a risk of postpartum hemorrhage.

## References

- ACOG Committee Opinion / SMFM Consult: Intrahepatic Cholestasis of Pregnancy (2021)
- Ovadia C et al. Association of adverse perinatal outcomes of intrahepatic cholestasis of pregnancy with biochemical markers: results of aggregate and individual patient data meta-analyses. Lancet. 2019;393:899-909
- Chappell LC et al. Ursodeoxycholic acid versus placebo in women with intrahepatic cholestasis of pregnancy (PITCHES): a randomized controlled trial. Lancet. 2019;394:849-860
- Williamson C, Geenes V. Intrahepatic cholestasis of pregnancy. Obstet Gynecol. 2014;124:120-133
- Glantz A et al. Intrahepatic cholestasis of pregnancy: relationships between bile acid levels and fetal complication rates. Hepatology. 2004;40:467-474