Hydronephrosis Risk Factors. Or a condition called reflux may cause urine to flow back into the kidneys from the bladder. Kidney stones are the common causes of hydronephrosis in both men and women.
Hydronephrosis is usually caused by another underlying illness or risk factor. If the cause of hydronephrosis in the first child is ureteropelvic junction (uvj) blockage, then the chances of its occurrence are as high as 50% in future children. However, most often babies are born with the condition.