Hi..... If the cause of the hydronephrosis is an obstruction and this is corrected, the child’s kidneys will be able to work properly. If the cause of the hydronephrosis is VUR that is not too severe, the child’s kidneys are also likely to work properly...... The child may need an operation to correct the reflux and their kidneys may be damaged. However, the earlier the hydronephrosis is discovered, the better the outcome for the child....Consult Urologist....