The sonographic appearance of normal and abnormal fetal genitalia.
OBJECTIVE
Prenatal sonography has evolved through advancements in imaging technology and observer experience. This review focuses on our current knowledge of the sonographic appearance of normal and abnormal fetal genitalia.


METHODS
A MEDLINE computerized reference and manual bibliography reviews were performed to find pertinent peer-reviewed articles on the sonographic appearance of normal and abnormal fetal genitalia.


RESULTS
The sonographic appearance of the normal fetal genitalia has been defined. The male phallus can be visualized as early as 10 to 11 weeks of gestation, while testicular descent is not seen before 26 weeks. Hydroceles are commonly detected. In the female subject the labia majora and labia minora are visible by 15 weeks. Hydrometrocolpos due to uterovaginal anomalies can be seen as early as 26 weeks.


CONCLUSIONS
Advances in prenatal sonography enable one to diagnose late first trimester gender. Sonography of the fetal genitalia complements fetal sex determination in cases of intersex, X-linked disorders or gender specific fetal anomalies, and is an important tool with increasing indications in prenatal medicine.
Shapiro
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Department of Urology, The New York University School of Medicine, New York, USA.
D005260:Female; D005333:Fetus / Q000002:abnormalities*; D005835:Genitalia / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D019849:Sex Determination Processes; D016216:Ultrasonography, Prenatal