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 (VUR) in baby boys.


METHODS
The findings of ultrasonography and voiding cysto-urethrography (VCUG) in 25 baby boys with VUR 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.


CONCLUSIONS
The bladder and urethral anomalies found in this series of patients with neonatal VUR 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.
Avni
E F
EF
Department of Radiology, Erasme Hospital, Brussels, Belgium.
Schulman
C C
CC
D004108:Dilatation, Pathologic; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018743:Perinatal Care; D014463:Ultrasonography; D014524:Urethral Obstruction / Q000196:embryology*; D014718:Vesico-Ureteral Reflux / Q000151:congenital / Q000000981:diagnostic imaging / Q000196:embryology*