Should the mode of delivery be altered in women with focal nodular hyperplasia (FNH) of the liver?

Management of Pregnancy and Delivery in Women with Focal Nodular Hyperplasia of the Liver

Women with focal nodular hyperplasia should be advised that pregnancy is not contraindicated and vaginal delivery is not associated with increased risks. 1

Understanding Focal Nodular Hyperplasia (FNH) in Pregnancy

Focal nodular hyperplasia is the second most common benign liver tumor with a prevalence of 0.3% to 3%, commonly diagnosed in reproductive-aged women 1. Key characteristics include:

• Affects females more commonly than males (estimated sex ratio of 26:1) 2
• May coexist with other vascular hepatic lesions, such as hemangiomas, in up to 20% of cases 1
• Characterized by hyperplastic or regenerative response to hyperperfusion through anomalous arteries 2

Evidence on FNH During Pregnancy

The relationship between FNH and pregnancy has been well-studied:

• The association between FNH and estrogen is not well established 1
• Multiple studies have shown no significant change in the size of FNH lesions during pregnancy 1
• In a study of 20 pregnant women with FNH, size remained constant in 7 patients, reduced in 10 patients, and only 3 had non-significant growth 1
• Only one case of hepatic rupture has been reported in the literature 1

Recommendations for Mode of Delivery

Based on the most recent and highest quality evidence:

• Vaginal delivery is not contraindicated in women with FNH 1
• No alteration in the mode of delivery is necessary specifically for women with FNH 1
• The European Association for the Study of Liver Diseases (EASL) provides a strong recommendation (Level of Evidence 4) that vaginal delivery is not associated with increased risks in women with FNH 1

Monitoring During Pregnancy

Unlike other liver lesions such as hepatocellular adenomas or hemangiomas:

• FNH does not require routine monitoring during pregnancy 1
• EASL guidelines specifically state: "Imaging is not routinely recommended to monitor focal nodular hyperplasia during pregnancy" (Level of Evidence 4) 1

Important Caveats and Rare Complications

While FNH generally follows a benign course during pregnancy, clinicians should be aware of:

• Extremely rare cases of FNH rupture have been reported in the literature 3, 4
• In one case report, FNH showed growth progression during pregnancy, but decreased in size two months after delivery 5
• These complications are exceedingly rare and do not warrant changes to standard obstetric management

Clinical Decision Algorithm

1. For women with known FNH planning pregnancy:

   • Reassure that pregnancy is not contraindicated
   • No pre-pregnancy interventions are required

2. For pregnant women with FNH:

   • No routine imaging surveillance is necessary
   • Standard obstetric care should be provided
   • Manage any symptoms (e.g., right upper quadrant pain) as they arise

3. For delivery planning:

   • Proceed with standard obstetric indications for mode of delivery
   • FNH alone is not an indication for cesarean section
   • Vaginal delivery is not associated with increased risks

By following these evidence-based recommendations, clinicians can provide appropriate care while avoiding unnecessary interventions or cesarean deliveries for women with focal nodular hyperplasia.