Accuracy of fetal sex determination in the first trimester of pregnancy using 3D virtual reality ultrasound.

<bold>Purpose: </bold>Early detection of fetal sex is becoming more popular. The aim of this study was to evaluate the accuracy of fetal sex determination in the first trimester, using 3D virtual reality.<bold>Methods: </bold>Three-dimensional (3D) US volumes were obtained in 112 pregnancies between 9 and 13 weeks of gestational age. They were offline projected as a hologram in the BARCO I-Space and subsequently the genital tubercle angle was measured. Separately, the 3D US aspect of the genitalia was examined for having a male or female appearance.<bold>Results: </bold>Although a significant difference in genital tubercle angles was found between male and female fetuses, it did not result in a reliable prediction of fetal gender. Correct sex prediction based on first trimester genital appearance was at best 56%.<bold>Conclusion: </bold>Our results indicate that accurate determination of the fetal sex in the first trimester of pregnancy is not possible, even using an advanced 3D US technique. [ABSTRACT FROM AUTHOR]