Impact of Cholestasis in Pregnancy on the Fetus
Intrahepatic cholestasis of pregnancy (ICP) carries significant risk to the fetus, including complications such as preterm delivery, meconium-stained amniotic fluid, respiratory distress syndrome, fetal distress, and stillbirth. 1, 2
Fetal Complications Associated with ICP
Stillbirth Risk
- Stillbirth is the most serious complication of ICP
- Risk correlates directly with maternal bile acid levels:
- High risk: ≥100 μmol/L - significantly increased stillbirth risk
- Moderate risk: 40-99 μmol/L - moderate stillbirth risk
- Lower risk: <40 μmol/L - lower stillbirth risk 2
- Most stillbirths occur in the third trimester
- Stillborn fetuses are typically appropriately grown without structural abnormalities 1
Other Fetal Complications
- Preterm birth (spontaneous or iatrogenic)
- Meconium-stained amniotic fluid
- Respiratory distress syndrome
- Fetal distress during labor 1, 3
- Sudden intrauterine fetal death 3
Pathophysiology of Fetal Complications
The exact mechanism of fetal complications in ICP is not fully understood, but likely involves:
- Elevated maternal bile acids crossing the placenta
- Direct toxic effects of bile acids on the fetal heart and other organs
- Impaired placental function
- Altered fetal metabolism 4, 5
Risk Stratification and Management
Monitoring
- Antenatal fetal surveillance should begin at a gestational age when delivery would be performed in response to abnormal testing results 1
- More frequent monitoring for patients with higher bile acid levels (≥100 μmol/L) 1
- Normal fetal testing does not eliminate stillbirth risk 2
Delivery Timing Based on Bile Acid Levels
- High Risk (≥100 μmol/L): Delivery at 36 0/7 weeks or at diagnosis if after 36 weeks 1, 2
- Moderate Risk (40-99 μmol/L): Delivery between 36 0/7 and 39 0/7 weeks 1, 2
- Lower Risk (<40 μmol/L): Delivery between 37-39 weeks 2
Treatment to Reduce Fetal Risk
- Ursodeoxycholic acid (UDCA) is the first-line treatment (10-15 mg/kg/day in divided doses) 1, 2
- UDCA may help reduce bile acid levels and potentially decrease adverse fetal outcomes 2
- Administer antenatal corticosteroids for fetal lung maturity if delivery occurs before 37 0/7 weeks 1
Important Considerations
- Continuous fetal monitoring during labor due to higher risk of stillbirth 1
- Preterm delivery before 37 weeks is not recommended without laboratory confirmation of elevated bile acids 1
- ICP is associated with other pregnancy complications that may affect the fetus, including preeclampsia (2.6-fold increased risk) and gestational diabetes 2
Pitfalls to Avoid
- Delaying delivery beyond recommended gestational age based on bile acid levels
- Failing to initiate appropriate fetal surveillance
- Overlooking the need for antenatal corticosteroids when delivery occurs before 37 weeks
- Assuming normal fetal testing eliminates stillbirth risk
- Underestimating the significance of maternal symptoms when bile acid levels are pending or initially normal 2
Early recognition, appropriate monitoring, timely intervention with UDCA, and delivery at the optimal gestational age based on bile acid levels are crucial to minimize adverse fetal outcomes in pregnancies complicated by ICP.