Prenatal diagnosis. Therapeutic implications.

Prenatal diagnosis of structural anomalies provides the opportunity to influence the postnatal outcome. The greatest value of antenatal screening is, in fact, the awareness of the urogenital abnormalities, such as presumed UPJ obstruction, so that appropriate investigation and treatment can be offered immediately after birth and before permanent damage occurs owing to obstruction or infection. Crombleholme and coworkers reported that prenatal consultation impacted favorably on outcomes by preventing early termination of pregnancy owing to misconceptions about the existing condition. It also permitted delivery of complex cases in a tertiary care setting, thereby preventing a delay in postnatal management. A systematic approach to the infant in the prenatal and postnatal periods is important. The natural history of prenatally detected hydronephrosis continues to be defined, and there is no ideal test to predict the outcome of UPJ obstruction. Several investigators are evaluating various markers in urine that may help to identify fetuses who require early postnatal intervention. More complete understanding regarding the natural history of unilateral pediatric UPJ obstruction and its response to surgery will not be available until several randomized, prospective clinical studies are completed. The collaborative effort of obstetricians, neonatologists, geneticists, radiologists, and pediatric urologists should provide answers to many questions surrounding prenatally diagnosed UPJ obstruction.