Prenatal Sonographic Clues to Diagnose External Genital Anomalies: Is It a Girl or a Boy?

Introduction The purpose of this study was to present the prenatal sonographic findings of external genital anomalies and determine diagnostic clues. Methodology In a single-center retrospective study, a total of 15,320 pregnant women underwent a routine ultrasound (US) screening between 18 and 40 weeks of gestation from March 2015 to January 2022. The fetuses with indeterminate sex and suspected genital anomalies were enrolled in the study. B-mod and three-dimensional (3D) imaging of the external genital organs were performed according to a local protocol in cases of genital anomalies. Prenatal and postnatal data were retrieved from the electronic health records. Results A total of 88 fetuses were included in the study. The prevalence of external genital anomalies was found to be 0.6%, and the degree of correspondence (DC) between prenatal and postnatal diagnoses of external genital anomalies was 94.3%. The most common genital anomaly was hypospadias with a frequency of 59%. Severe hypospadias was detected in five of six cases with chordee where the penoscrotal angle was below 30°. Approximately 70% of clitoromegaly cases with labial hypertrophy had a horseshoe sign on 3D images. Conclusions The DC between prenatal and postnatal diagnoses of external genital anomalies is high in this study. The novel diagnostic clues, such as horseshoe sign and penoscrotal angle may be useful in diagnosing and determining the severity of the external genital anomalies.