Optimizing postnatal management based on prenatal UTD grading: a 5-year follow-up study of fetal hydronephrosis in a large Chinese cohort
摘要
To investigate the long-term natural history of fetal hydronephrosis (FH) in a Chinese population, identify key prognostic factors, and optimize evidence-based postnatal management strategies using the Urinary Tract Dilation (UTD) classification system.
MethodsA hybrid retrospective-prospective cohort study was conducted among 49,097 pregnant women who received prenatal screening at Beijing Children’s Hospital Shunyi Women’s and Children’s Hospital between January 2010 and March 2020. A total of 2,263 fetuses were diagnosed with hydronephrosis and followed for 5 years. Prenatal ultrasound parameters (anteroposterior renal pelvic diameter [APD], renal parenchymal thickness, and A/R ratio) and postnatal outcomes (surgery, urinary tract infections, hypertension) were analyzed. Cases were stratified into UTD A1 (low-risk) and A2 ~ 3 (high-risk) groups. Statistical analyses included generalized linear mixed-effects models (GLMM), cumulative link mixed models (CLMM), and generalized linear models (GLM).
ResultsThe incidence of fetal hydronephrosis was 4.61% (2,263/49,097). Among these, 9.01% (204/2,263) were confirmed postnatally, and only 0.75% (17/2,263) required surgery. By the final assessment at the 5-year follow-up, hydronephrosis had resolved spontaneously in 97.39% (2,204/2,263) of cases, with persistence in only 59 (2.61%). Multivariate analysis identified left renal APD (OR = 22.05, 95% CI: 21.99–22.11, p < 0.001) and left A/R ratio (OR = 22.39, 95% CI: 1.31–383.89, p = 0.03) as independent predictors for surgery. All surgical cases were in the UTD A2 ~ 3 group, which showed significantly higher risks of postnatal hydronephrosis (OR = 8.26, p < 0.001), persistence at 5 years (OR = 8.30, p < 0.001), and clinical symptoms (OR = 20.57, p < 0.001) compared to the UTD A1 group.
ConclusionMost cases of fetal hydronephrosis resolve spontaneously without intervention. The UTD system effectively stratifies postnatal risk. For asymptomatic infants in the UTD A1 group, routine ultrasound within the first year of life is sufficient, reducing unnecessary early imaging and family anxiety. APD and A/R ratio are critical imaging predictors for surgical decision-making.