Natural Course of Congenital Hydronephrosis in Infants Aged 0-6 Months

Exclusion Criteria

• •Presence of other severe congenital malformations that may affect follow-up or prognosis assessment, such as congenital heart disease, biliary atresia, spina bifida, etc.
• •Secondary hydronephrosis caused by acquired factors (e.g., urinary system tumors, stones, trauma) or well-defined genetic metabolic diseases.
• •Having received interventional treatments prior to enrollment, such as surgical procedures related to hydronephrosis (e.g., pyeloplasty) or pharmacological interventions (e.g., long-term use of diuretics).
• •Severe underlying diseases that preclude tolerance for long-term follow-up, such as severe infections, respiratory failure, or renal failure (e.g., glomerular filtration rate \< 30 ml/min/1.73m²).
• •Inability of the legal guardian to cooperate due to mental illness, cognitive impairment, or refusal to comply with follow-up schedules and data collection requirements.