Three-dimensional multiplanar ultrasound for fetal gender assignment: value of the mid-sagittal plane

Objective To evaluate the feasibility and accuracy of fetal gender assignme nt from three-dimensional ultrasound (3D US) data at 10-24 weeks' gestation . Methods Three-dimensional ultrasound volume data on 47 fetuses were reviewe d and divided into groups: 10-14, 15-18, and 19-24 weeks. Fetal genitalia w ere studied in axial and sagittal planes for gender assignment, using publi shed criteria. The moss valuable plane for assignment was noted. Gender ass ignment was compared with gender at birth. Results Gender assignment was possible in 44 of 47 fetuses; 25 assigned mal e and 19 female. Between 10 and 14 weeks the mid-sagittal plane alone was d iagnostic for all fetuses. Accuracy of assignment between II and 14 weeks w as 100%. Between 15 and 18 and 19 to 24 weeks, male assignment was 100% acc urate. Female assignment was 100% accurate between 15 and 18 weeks. Accurac y decreased to 60% in the 19 to 24 week group, however, in two of the five cases in which gender was wrongly assigned to be male, the assignment was p rospectively considered doubtful due to poor resolution of volume data. Exc luding these two cases, accuracy for female assignment in the 19-24 week gr oup was 100%. Conclusion Using 3D US, gender assignment was possible in 44 of 47 of fetus es, as early as 11 weeks' gestation. In early gestation, 11-14 weeks, accur acy of male and female gender assignment was 100%.