Congenital Hydronephrosis

Congenital hydronephrosis refers to the swelling (dilation) of the kidney’s drainage system due to urine buildup. It is often discovered during routine prenatal ultrasounds and varies from mild to severe depending on the cause and extent of obstruction or urine backflow.

1. Physiologic (Transient) Hydronephrosis

Temporary and often resolves spontaneously without treatment.

2. Obstructive Hydronephrosis

Caused by physical blockage, such as:

Ureteropelvic junction (UPJ) obstruction

Ureterovesical junction (UVJ) obstruction

Posterior urethral valve (PUV)

3. Reflux-related Hydronephrosis

Due to vesicoureteral reflux (VUR), where urine flows backward from the bladder to the kidney.

Many infants are asymptomatic and diagnosed via imaging.

• Developmental abnormalities in the urinary tract during fetal growth
• Obstructive lesions (e.g., UPJ obstruction, PUV)
• Genetic predisposition or family history of urinary tract malformations
• Male gender (higher incidence)

Although the condition itself cannot be prevented, early detection through routine prenatal ultrasound enables close monitoring and timely management, reducing the risk of kidney damage.