2D and 3D Ultrasound Examination of Labia Minora

The aim of the study was to prospectively evaluate, by using 2D/3D ultrasonography and 3D color Doppler analysis, the morphological and vascular changes in the labia minora during the menstrual cycle of women not sexually aroused. A total of 81 young, healthy eumenorrheic women, in a stable heterosexual relationship (>1 year) and without any sexual dysfunction, underwent 2D/3D ultrasound and color Doppler examination of the labia minora on Days 3-5 and 12-14 of the menstrual cycle. Estradiol serum levels were also evaluated. Estradiol plasma levels increased in the periovulatory phase. The labia minora thickness increased from the follicular (3.8 ± 0.3 mm) to the periovulatory phase (4.6 ± 0.4 mm; p = .005). Furthermore, in the periovulatory phase, the vaginal introitus area and the angles were wider than in the follicular phase. The Pulsatility Index of the posterior labial artery significantly decreased in the periovulatory period. Three-dimensional power Doppler indices of vascularization and blood flow in the labia minora significantly increased in the periovulatory period. The relationship between the different parameters showed that estradiol was positively correlated with labia minora thickness and vaginal introitus area and angles. Furthermore, the circulating levels of estradiol were negatively correlated with posterior labial artery PI and positively correlated with other indices of labia minora vascularization. In conclusion, it seems that estrogen production may influence the anatomic and vascular changes of the labia minora during the menstrual cycle and these changes can be easily identified by ultrasound.