Fetal Hepatic Calcification (Fetal Liver Calcifications - FLCs)

Definition

Incidence

• Echogenic hepatic lesions: approximately 5-6 per 10,000 pregnancies
• Overall prevalence estimated at 5-10 per 10,000 births
• Cholelithiasis (gallstones): ~0.5%, almost always in the 3rd trimester

Etiology and Pathogenesis

Intrahepatic Parenchymal

On Hepatic Peritoneal Surface

Diagnostic Features on Ultrasound

• Appear as hyperechoic (bright) foci in the fetal abdomen or liver
• May produce posterior acoustic shadowing (classic for true calcification)
• Location matters:
  • Intrahepatic (parenchymal) - infection, vascular, tumor
  • Peritoneal surface of liver - meconium peritonitis
  • Gallbladder fossa - cholelithiasis

Important caveat: Harmonic-enhanced imaging and higher-frequency transducers can overexaggerate echogenicity. Harmonic imaging should be disabled before confirming the finding, as apparent echogenic lesions may disappear when harmonics are turned off.

Associated Anomalies

• Multiple intrahepatic echogenic foci are more often associated with TORCH infection or aneuploidy (poorer prognosis)
• Isolated singular lesions are more likely benign (e.g., hepatic hemangioma)
• All fetal organs should be assessed to rule out other congenital malformations and genetic syndromes
• Look for: cerebral calcifications, ventriculomegaly, hydrops (suggest TORCH), fetal growth restriction, cardiac/renal anomalies

Multiple echogenic foci in the fetal abdomen or liver are likely to be associated with infection or meconium peritonitis, whereas isolated echogenic foci are more likely benign.

Workup / Investigations

1. Detailed anomaly scan - assess all fetal organs; rule out structural defects, cardiac anomalies, CNS involvement
2. Maternal serology (TORCH titers) - IgM and IgG for toxoplasmosis, CMV, rubella, herpes; if CMV IgM positive, perform CMV avidity testing (low avidity = recent primary infection)
3. Maternal STORCH screen - syphilis, toxoplasma, CMV, rubella, herpes
4. Cystic fibrosis carrier status testing
5. Maternal AFP and hCG - may help determine etiology and prognosis
6. Fetal karyotype / chromosomal microarray - if multiple anomalies or markers of aneuploidy present
7. Fetal echocardiography
8. Fetal MRI - helpful when ultrasound findings are indeterminate
9. Serial ultrasound - monitor fetal growth, amniotic fluid, and worsening condition; nonstress testing/biophysical profile twice weekly from 32-34 weeks if persistent echogenicity and/or fetal growth restriction
10. Delivery at a tertiary care facility if persistent echogenicity, associated fetal abnormalities, or FGR is present

Prognosis

• Isolated FLCs, even when coarse, do not appear to impact fetal or neonatal outcomes when potential causes are excluded (2025 BMJ Case Reports, PMID: 40713069)
• Long-term prognosis depends mostly on associated abnormalities and/or underlying disease

Neonatal Management

• Continue postnatal imaging: ultrasound, plain abdominal X-ray, upper/lower GI barium studies, MRI
• Expectant management appropriate if investigation is unremarkable
• Surgical treatment may be warranted for bowel obstruction with or without perforation, volvulus, ascites, pneumoperitoneum
• Pediatric surgery consultation as appropriate

Summary Points

• FLCs are uncommon but important prenatal ultrasound findings with a broad differential
• The key discriminator is whether they are isolated vs. multiple - isolated lesions tend to be benign while multiple lesions suggest infection or chromosomal abnormality
• A structured work-up (TORCH screen, CF carrier status, karyotype, detailed anatomy scan) is essential
• When all investigations are normal, prognosis is excellent and isolated FLCs can be managed expectantly with serial monitoring