The aim of this study is to evaluate the significance of renal pelvis aspiration (RPA) in the management of antenatal hydronephrosis (AHN). This study enrolled 15 AHN cases (one twin pregnancy) that necessitated RPA for AHN. Chromosomal abnormalities, gene disorders, and additional life-threatening congenital abnormalities were eliminated prior to intrauterine interventions. Urine analysis were performed for the evaluation of renal function. Normal renal function was observed in six neonates/infants (40%) (group 1), whereas impaired renal function and various type of urinary system anomalies were observed in 9 neonates/infants (60%) (group 2) during the short-term and longitudinal follow-up periods. There were statistically significant differences in the oligohydroamniosis rate, mean fetal urine sodium value, mean fetal urine beta 2-microglobulin, mean gestational week at birth, and mean birthweight values between the groups (P = 0.007, P < 0.001, P = 0.035, P < 0.001, and P = 0.001, respectively). Renal pelvis aspiration and urine analysis were substantial for the management of AHN in necessary cases. beta 2-microglobulin and sodium are clinically useful markers to detect the presence of severe renal damage due to obstructive uropathy and thus, important adjuvants in the proper selection of fetuses for further antenatal interventions.