Identification of Fetal Gender by Ultrasound at 11th to 14th Weeks of Gestation - Revista Brasileira de Ginecologia e Obstetrícia

Purpose: to determine the feasibility of early ultrasonographic identification of fetal gender. Methods: a prospective study in a University Department of Obstetrics and Gynecology. A total of 592 women underwent ultrasonography at 11-14 weeks of gestation. Fetal gender was identified according to genital tubercle position (vertical or horizontal) at sagittal plane and confirmed at birth or by karyotype analysis. Results: the overall accuracy of correctly assigning fetal gender was 84%. The success of identification increased with gestational age, being 72%, 85% and 89% at 11, 12 and 13 weeks, respectively. The accuracy of correctly identifying fetal sex significantly changed with operator training, being 83.5% at the beginning and 93.6% at the end of the study. Conclusion: ultrasound determination of fetal gender is feasible, with good accuracy and may be of potential use to avoid invasive testing in family histories of X-linked disorders.