Antenatal Urinary Tract Dilatation Assessment Using "UTD Classification System" and Its Association With Post-Natal Outcomes in a Tertiary Care Center: A Prospective Observational Study.

Objectives: To study the antenatal follow-up of fetal urinary tract dilation (UTD) and its post-natal outcomes using the standard "UTD Classification System."

Methodology: In this prospective observational study, fetuses diagnosed with urinary tract dilatation were classified based on the multidisciplinary "UTD Classification System" and were followed up throughout the pregnancy and postnatally for 1 year. We excluded fetuses with additional structural abnormalities, genetic disorders, or intrauterine fetal death.

Results: During the study period, 46 108 antenatal scans were conducted; according to the eligibility criteria, 593 fetuses were included for analysis, with 81% belonging to the A1 group and 19% to the A2-3 group. The rate of antenatal resolution was significantly higher in the A1 group (64%) compared to the A2-3 group (3%) (p < 0.05). The female gender was protective and had higher spontaneous prenatal resolution among UTD A1 fetuses. However, post-natal persistence at 1 year (49% vs. 0.2%) and the need for surgery (32% vs. 1%) were higher in the A2-3 group. Higher maximum anteroposterior renal pelvic diameter (APRPD) and ureteric abnormalities in the last scan were independent predictors for surgery.

Conclusion: Ours is one of the largest prospective studies on UTD classification. Key points noted in this study are that most of the resolving UTDs were from UTD A1, and obstructive uropathies were from the UTD A2-3 group. Higher maximum APRPD and ureteric abnormalities were independent predictors for surgery in the UTD A2-3 group.