Predictive value of ultrasound in prenatal diagnosis of hypospadias: hints for accurate diagnosis.

OBJECTIVES: This study aims to assess the diagnostic accuracy of targeted ultrasound examination in prenatal diagnosis of hypospadias and to evaluate the predictive values of defined ultrasonographic findings of hypospadias. METHODS: The cases diagnosed with hypospadias in our fetal medicine center were identified on an electronic database. The ultrasound reports, images and hospital records were reviewed retrospectively. The predictive value of prenatal ultrasound diagnosis and the predictive values of each sonographic finding were assessed according to the postnatal clinical examinations. RESULTS: Thirty-nine cases were diagnosed with hypospadias on ultrasound during the 6 years. Nine fetuses with missing postnatal examination records were excluded. Twentytwo of the remaining fetuses had their prenatal diagnosis of hypospadias confirmed in postnatal examinations, indicating a 73.3 % positive predictive value. Normal external genitalia was detected in postnatal examinations of three fetuses. Five fetuses were diagnosed with other external genital abnormalities, including micropenis (n=2), clitoromegaly (n=2), and buried penis with bifid scrotum (n=1) in postnatal examinations. The positive predictive value of prenatal ultrasound for any external genital abnormality was 90 %. CONCLUSIONS: Although the positive predictive value of ultrasound for genital anomalies is satisfying, it is slightly lower for the specific diagnosis of hypospadias. This reflects overlapping ultrasound findings of different external genitalia anomalies. Standardized, systematic evaluation of the internal and external genital organs, karyotyping and genetic sex determination are essential to achieve a precise prenatal diagnosis of hypospadias.