[Dilemma of antenatal diagnosis of obstructive uropathy and its treatment]

The early ultrasound detection of fetal urinary dilatations raises dilemmas about their physiological and pathological meanings. Dilatation does not always mean pathological obstruction of the urinary tract. The chronology of the embryology of the Wolffian system is partially unknown and some hypotheses can be developed concerning the urine drainage in the fetus. The physiology of the fetal kidney is also unclear because of the inadequacy of the functional assessments and their dependence on the mother's parameters. The study of the pressures inside the different segments of the fetal urinary tract could be an efficient tool in the understanding of its progressive permeabilization. The difference between primary kidney dysgenesis and kidney dysplasia secondary to urine hyperpressure appears to be of paramount importance in the fetal treatment of these dilatations and in the long-term prognosis. Thus one can better understand how difficult the decision of shunting the fetal urine toward the amniotic cavity. Can be no one can prove its benefit for the fetal development and some lethal complications of these in utero procedures have been described. However, this new approach of the fetal urinary tract obstruction leads us to a change in the therapeutic attitudes in newborns, which stresses a better understanding of this development.