Development of a fetal renal ultrasound score for predicting neonatal renal dysfunction.

Introduction: Neonatal renal dysfunction is a congenital abnormality of renal development caused by disrupted interaction between the ureteric bud and the metanephric blastema, resulting in disorganized renal parenchyma and variable degrees of functional impairment. Prenatal diagnosis remains challenging due to the limited specificity of ultrasound findings and the frequent need for postnatal confirmation. A standardized prenatal ultrasound score may improve identification of fetuses at higher risk of neonatal renal dysfunction among those with suspected renal abnormalities. Methods: We conducted a single-center retrospective observational study including 59 pregnancies with fetuses showing ultrasound features suggestive of renal pathology. A prenatal ultrasound score was constructed using five routinely assessed parameters: renal parenchymal hyperechogenicity, hydronephrosis severity, renal longitudinal diameter, corticomedullary differentiation, and amniotic fluid index. Postnatal renal outcome was determined using clinical, radiological, and/or histopathological data. Results: A prenatal ultrasound score ≥ 6 was associated with a predicted probability of neonatal renal dysfunction exceeding 50%. A progressive dose-response relationship was observed between increasing prenatal scores and adverse renal outcomes. Fetuses diagnosed postnatally with neonatal renal dysfunction had significantly higher prenatal ultrasound scores compared with those with similar prenatal findings but preserved renal function at birth. Conclusions: A composite prenatal ultrasound score integrating routinely assessed renal parameters is associated with neonatal renal dysfunction in fetuses with suspected renal pathology. Higher scores identify an increasing risk of adverse renal outcome and may support prenatal prognostic assessment.