Prenatal Diagnosis of Posterior Urethral Valves: Timing of Diagnosis and Mid‐Term Renal Function When Second and Third Trimester Ultrasounds Are Systematically Performed

ABSTRACT Objective The impact of prenatal diagnosis timing in posterior urethral valves is unclear. We aimed to compare renal function between patients with suspected PUV diagnosed before or after 28 weeks of gestation in a population who underwent systematic T2 and T3 ultrasounds. Methods We performed a retrospective analysis of a prospective cohort of patients with prenatally suspected and postnatally confirmed PUV. Patients were stratified by timing of prenatal ultrasound detection of urinary tract abnormalities (T2 vs T3). We compared nadir creatinine and mid‐term eGFR (> 5 years of follow‐up). Results 72 boys with postnatally confirmed PUV were included. Thirty‐seven patients (51%) were diagnosed before 28 weeks' gestation (T2 group). This early group had significantly higher NC values (median 38 vs. 26 μmol/L, p < 0.05) and lower eGFR at mid‐term follow‐up (median 85 vs. 105 mL/min/1.73 m 2 , p < 0.05) compared to the T3 group. Conclusions PUV suspected during the second trimester of gestation is associated with significantly worse NC and mid‐term renal function compared with those suspected later in pregnancy (T3). Reports of prenatal diagnosis of PUV should dichotomize between T2 and T3 diagnoses. The true rate of PUV that could be diagnosed prenatally is higher than expected.