Prenatal diagnosis of liver and biliary tract disease.

The diagnosis and detection of some forms of liver and bile duct disease have become possible since the adoption of routine fetal ultrasound scanning in the UK, and the remarkable advances in molecular biological techniques. Nevertheless, although antenatal detection may well have improved, it remains difficult to offer a specific diagnosis, much less a prognosis, in most cases. Cystic dilatation of the biliary tree is probably the most common finding. This may be due to cystic choledochal malformations or, occasionally but crucially, biliary atresia. Postnatal investigations (such as ultrasonography, magnetic resonance cholangiography and liver histology) must take the latter possibility into account, as early surgery is the key to a successful outcome following reconstructive biliary surgery. Antenatally diagnosed liver tumours are usually of vascular origin and have an unpredictable natural history. Some may cause fetal cardiac failure and are candidates for in-utero intervention, but in all likelihood, a large proportion will resolve without specific therapy.