Transvaginal three-dimensional ultrasound assessment of embryonic genital tubercle at 8-10+6 weeks of gestation

Toshiyuki Hata; Tomomi Kawahara; Riko Takayoshi; Yasunari Miyagi; Takahito Miyake

doi:10.1515/jpm-2024-0081

Transvaginal three-dimensional ultrasound assessment of embryonic genital tubercle at 8-10+6 weeks of gestation

J Perinat Med. 2024 May 15. doi: 10.1515/jpm-2024-0081. Online ahead of print.

Authors

Toshiyuki Hata^{1

2}, Tomomi Kawahara¹, Riko Takayoshi^{1

2}, Yasunari Miyagi³, Takahito Miyake^{1

2}

Affiliations

¹ Department of Obstetrics and Gynecology, Miyake Clinic, Minami-ku, Okayama, Japan.
² Department of Perinatology and Gynecology, Kagawa University Graduate School of Medicine, Miki, Kagawa, Japan.
³ Department of Gynecology, Miyake Ofuku Clinic, Minami-ku, Okayama, Japan.

PMID: 38742481
DOI: 10.1515/jpm-2024-0081

Abstract

Objectives: To assess embryonic genital tubercle using transvaginal three-dimensional (3D) ultrasound at 8-10+6 weeks of gestation.

Methods: One-hundred and two transvaginal 3D ultrasound scans were performed for first-trimester dating at 8-10+6 weeks of gestation. The genital tubercle angle (GTA) and genital tubercle length (GTL) were measured with a mid-sagittal view of the embryo using the 3D ultrasound multiplanar mode. Intra- and inter-observer agreements regarding GTA and GTL were also assessed with Bland-Altman plots and intra- and inter-correlation coefficients.

Results: There were no significant differences in GTA between male and female embryos at 8, 9, 10 weeks, or 8-10+6 weeks of gestation, respectively. There were also no significant differences in GTL between male and female embryos at 8, 9, 10 weeks, or 8-10+6 weeks of gestation, respectively. However, GTL increased linearly with advancing gestation (r=0.8276, p<0.00001). Mean GTL (SD) values at 8, 9, and 10 weeks were 0.833 mm (0.274), 1.623 mm (0.262), and 2.152 mm (0.420), respectively (p<0.001). Intra- and inter-reproducibilities of GTA and GTL were excellent. The intra- and inter-correlation coefficients of GTA and GTL were 0.964 and 0.995, and 0.996 and 0.9933, respectively.

Conclusions: The genital tubercle could be identified using transvaginal 3D ultrasound at 8-10+6 weeks of gestation. However, sex differentiation could not be performed at this age. The genital tubercle linearly developed with advancing gestation during the mid-first trimester of pregnancy.

Keywords: 3D ultrasound; embryo; fetus; genital tubercle angle; genital tubercle length; mid-first trimester.