Prenatal diagnosis, management and outcome of fetal uretero-pelvic junction obstruction.

Prenatal diagnosis, management and outcome were studied retrospectively in 24 cases of unilateral and bilateral uretero-pelvic junction obstruction (UPJO). Moderate-to-marked pelvic dilatation was documented in 19 out of 24 cases. The low morbidity and mortality observed in this study are probably determined by the late (third trimester) detection of UPJO, resulting in an underestimation of the prevalence of more severe renal pathology. Amniotic fluid was increased in 4 out of 14 cases of unilateral UPJO and in 5 out of 10 cases of bilateral UPJO, the underlying mechanism of which is still unclear. There was no oligohydramnios. The incidence of extrarenal structural pathology was low, i.e., 3 out of 24 cases. A close agreement could be demonstrated between pre- and postnatal sonographic grading of pelvic dilatation. However, postnatal ultrasonic grading of pelvic dilatation correlated poorly with the degree of functional obstruction as determined by IVP and lasix renography. Despite the severity of pelvic dilatation in the majority of cases, enlarged kidneys were revealed by postnatal clinical examination in only three instances, underlining the importance of prenatal sonographic detection of UPJO.