Prenatal diagnosis of fetal megabladder and urethral agenesis.

This is a case report of antenatal ultrasonographic detection of an enlarged fetal urinary bladder. Serial sonographic examinations revealed a large unilocular fetal intraabdominal mass. Cystocentesis and amniocentesis under ultrasonic control were preformed as well as an amniogram to establish the diagnosis. This is the fourth reported case in the English literature of fetal urethral agenesis diagnosed during the prenatal period. Early detection of potentially lethal fetal malformations is feasible with detailed examination of fetuses at risk.