P16.16: Fetal gender determination at 12-14 weeks of pregnancy using the “axial view”

Abstract

Our main goal was to test the feasibility and accuracy of fetal sex determination using the “axial view” method at 12–14 weeks gestation, and compare the method to the classical mid-sagittal view. Fetal gender assessment by transabdominal ultrasound was performed in 110 singleton pregnancies at 12–14 weeks of gestation using a technique we described as the “axial view”. The genital region was examined in an axial section showing the proximal extremities of both femurs and the genital tubercle. A line was traced between the femurs proximal extremities, and the positioning of the genital tubercle was analyzed according to this line. When more than half of the extension of the tubercle was positioned distally to the line, the fetus was considered of male gender, and when less than half was positioned this way the fetus was considered to be of the female gender. The mid-sagittal section was also performed, and the 30° was used as a cut-off. The crown-rump length (CRL) was measured in all cases. Fetal sex determination using the “axial view” was possible in 104 (94.5%) of the 110 fetuses. The CRL of the 6 cases were determination was not possible was below 60 mm. Phenotypic sex was confirmed in all 106 fetus. The accuracy of gender assignment using the “axial view” was 100% at all ages. Using the mid-sagittal view, we observed an accuracy of 98% for male gender assignment and 94% for female gender assignment. Prenatal gender assignment by ultrasound using the “axial view” has a high accuracy rate at 12–14 weeks.