Use of three-dimensional ultrasonography for prenatal diagnosis of ambiguous genitalia

Sex identification is one of the prime expectations of any parent during th e prenatal ultrasound examination. However, the ability to visualize fetal genitalia not only has important social implications but also has considera ble medical implications. Various endocrine disorders and complex genitouri nary malformations can be manifested in the form of anomalous genitalia, an d a delay in diagnosis may lead to an increase-in postnatal morbidity and m ortality.(1) In addition, correctly identifying and illustrating major feta l anomalies is of paramount importance to the parents, whose decisions rega rding possible termination will directly affect the course of the pregnancy . Prenatal detection of genital abnormalities is therefore helpful in evalu ating those fetuses with severe multisystem diseases and those with disorde rs more easily corrected with prenatal and neonatal treatments. Ambiguous g enitalia is a condition that affects approximately 1 per 5000 live-born inf ants. Until the inception of three-dimensional (3D) ultrasonography, two-di mensional (2D) ultrasonography was the only method available to visually de tect cases of ambiguous genitalia. A review of the literature reveals sever al case reports and small case series of prenatal identification of abnorma l fetal genitalia during targeted 2D ultrasonographic surveys. However, the limitations of a standard 2D fetal sonogram are often evident. We present a case of ambiguous fetal genitalia whose diagnosis was both correctly iden tified and visually clarified by the use of prenatal 3D ultrasonography.