Updates in the Management of Antenatal Hydronephrosis—from Current Practices to On-going Challenges

Purpose of Review: Antenatal hydronephrosis is the most commonly detected abnormality on routine prenatal ultrasound. Given that it is associated with a wide range of causes—from a self-resolving/benign finding, to severe disease with increased risk of morbidity and mortality—there continues to be much debate in attempting to standardize its approach. The purpose of this review is to summarize the currently proposed guidelines for its evaluation and management, across the spectrum from mild to severe disease. Recent Findings: Given the number of existing grading systems and guidelines, the practical management of antenatal hydronephrosis, along educating and counseling families, requires a fairly nuanced understanding of the currently proposed recommendations. Although mild-moderate grades of hydronephrosis have high rates of spontaneous resolution and can often be followed conservatively, more severely affected patients require additional investigation and possible surgical intervention, while the highest risk patients diagnosed in-utero present their own unique set of clinical challenges, calling for additional evidence to guide the evolving practices in maternal/fetal interventions. Summary: Optimizing the evaluation of antenatal hydronephrosis aims to identify infants with clinically significant abnormalities while avoiding unnecessary testing. Further research directed at predicting outcomes, across all patients from those with mild findings to severe disease, is needed to refine management of this challenging diagnosis.