Antenatal diagnosis of multicystic renal dysplasia

Multicystic Renal Dysplasia (MRD) was discovered during antenatal ultrasoun d examination in 138 fetuses between 1980 and 1995. Associated malformation s were present in 66% (42% urological) and 22% of the fetuses did not survi ve the pregnancy or the peri-natal period. Anatomical analysis showed a wider variety of MRD than in classical descrip tions. Obstruction of the urinary tract was almost invariable. Like the hyp othesis published by Beck in 1971, our view is that, with a very early obst ruction of the urinary tract (during the first trimester), there is a dyspl astic evolution of renal tissue, while later in pregnancy the same obstruct ion can induce a hydronephrosis with corticomedullary dysplasia. We advise complete neonatal urological investigation, and surgical removal of multicy stic kidneys, to avoid multiple and inadequate evaluations of those childre n with a single functioning renal unit.