The origin of vesico-ureteric reflux in male newborns: Further evidence in favour of a transient fetal urethral obstruction

Objective To present further arguments supporting a transient urethral obstruction occurring during early fetal development as an explanation of the origin of vesico-ureteric reflux (WR) in baby boys. Patients and methods The findings of ultrasonography and voiding cysto-urethrography (VCUG) in 25 baby boys with WR were reviewed, studying mainly bladder and urethral anomalies on VCUG and bladder-wall thickness on ultrasonography, Results A bladder or urethral anomaly was found in 15 patients, comprising isolated posterior urethral dilatation in five, posterior urethral dilatation with a bladder anomaly in four, tubular appearance of the urethra in two and bladder neck hypercontractility with diverticulae in four, Bladder-wall thickness ranged from 1 to 8 mm (mean 3.7) and in eight patients, the thickness exceeded 5 mm, Conclusion The bladder and urethral anomalies found in this series of patients with neonatal WR could be explained by a transient bladder outlet obstruction that possibly occurred in utero, These findings support the theory that a significant number of cases of VUR seen in baby boys result from a transient fetal urethral obstruction.