·         Transplacental infection- These include viral infections such as CMV, rubella, coxsackie and varicella. Other associated infections include toxoplasmosis and syphilis.

 

·         Hemolysis- Rh incompatibility, isoimmunization and congenital hemolytic anemia, e.g. spherocytosis.

 

 

·         Venous congestion-Congenital heart disease with right sided and biventricular heart failure.

 

·         Hepatic masses- These are mostly neoplastic and include hemangioma, mesenchymal hamartoma, hepatoblastoma, hepatic adenoma, hemangiopericytoma and metastases, e.g. neuroblastoma. Solitary cysts or polycystic disease of the liver may also cause hepatomegaly.

 

 

·         Metabolic disorders- These include galactosemia, trypsinemia, a1-antitrypsin deficiency, disorders of the urea cycle, methylmalonic acidemia and sialidosis.

 

·         Beckwith-Wiedemann syndrome- Sonographic features include visceromegaly, hemihypertrophy, increased renal cortical echogenicity, omphalocele or umbilical hernia.

 

 

·         Zellweger's syndrome-Sonography may reveal limb anomalies such as talipes equinovarus, rocker-bottom feet, bell-shaped thorax, cerebral ventricular dilatation and renal cysts. Analysis of amniotic fluid reveals deficiency of the enzyme dihydroxyacetone phosphate acyltransferase in the amniotic fluid cells, and the absence of peroxisomes in cultured amniotic fluid cells.