Failure of Prenatal Ultrasonography to Identify Classic Bladder Exstrophy in a Heavily Screened Population

Abstract

Objective

To summarize the imaging characteristics of newborns with bladder exstrophy and to identify the pitfalls that led to prenatal misdiagnosis.

Methods

We evaluated prenatal ultrasonographic reports of all consecutive newborns with bladder exstrophy seen in our institution between 2017-2023. None had been diagnosed prenatally on early (14-16 weeks' gestation) and late (18-24 weeks' gestation) second trimester sonographic scans.

Results

The study cohort included 14 patients after exclusion of four with insufficient information and one who was correctly diagnosed prenatally. All 14 had complete early and late second trimester scans. All had normal amniotic fluid volume. Biparietal diameter, head and abdominal circumferences, femur length, and fetal weight estimations were between 10-90 percentiles in both scans. All were erroneously diagnosed as having normal bladders, abdominal walls, and cord insertions. Two patients were diagnosed with suspected hypospadias in the late scan: both underwent a third directed scan and were again diagnosed with hypospadias without mention of other parts of the genitourinary tract.

Conclusion

Visualization of the filling of the bladder, meticulous examination of cord insertion and abdominal wall defects and a comprehensive examination of the genitourinary tract when there is a suspected penile anomaly can successfully identify cases of bladder exstrophy.