Ultrasound screening of urinary malformations in 'normal' newborns.

Abstract

To determine: (1) the incidence in newborns of both significant urinary anomalies and mild hydronephrosis; (2) the degree of inaccuracy of prenatal sonography in our area, and (3) the evolution of neonatal hydronephrosis. Using ultrasound, we examined 4,130 consecutive newborns, of which only 12 had a positive prenatal sonography. We distinguished 2 grades of hydronephrosis: mild (pelvic diameter between 5 and 15 mm), and significant (pelvic diameter > 15 mm). In the 'normal' newborns (with negative prenatal sonography), we found 0.9% significant urinary anomalies and 5.2% mild hydronephroses. Mild hydronephroses improved or disappeared spontaneously in 82% of the cases. 50% with significant dilatation required surgical correction. Neonatal ultrasound screening is essential for the early detection of uropathies missed on prenatal examination. The majority of mild hydronephroses detected in the newborn improve or disappear spontaneously. We hypothesize a relationship between the degree of dilatation, obstruction and evolution.