The objective of our study is to determine the thickness of the pubovisceral fasciculus of the levator ani muscle and the area of the genital hiatus by means of three-dimensional perineal ultrasound, in pregnant women in the 2nd trimester, and to analyze the related maternal, perinatal and postpartum clinical variables. Furthermore, to compare the results of our study with two similar series previously published. An observational, prospective study of pelvic floor ultrasound was carried out, performed at week 20, whose delivery was attended in the obstetrics service of the Hospital General Universitario Gregorio Marañón de Madrid (HGUGM), during the period of August from 2021 to June 2022. Maternal, ultrasound, perinatal and postpartum clinical variables were collected from each participant. During the study period, a total of 54 patients were included in it. The mean gestational age at which the ultrasound was performed was 19.81 ± 0.91 weeks. In relation to the ultrasound variables, the mean thickness of the pubovisceral muscle was 0.87 ± 0.13 cm (95% CI, 0.64-1.38 cm), while, in the plane of minimum dimension of the genital hiatus, the hiatal area at rest was 13.41 ± 3.22 (95% CI, 4.60-18.78) cm2. There is a significant correlation between the age of pregnant women (over 35 years of age) and the increase in the area of the genital hiatus (r = 0.295, p = 0.031). 3D ultrasound of the pelvic floor performed at week 20 of gestation can to be an effective, non-invasive, reproducible and cheap tool in the prognosis of the development of labor and of possible subsequent perineal dysfunctions.
Keywords: 3D ultrasound; levator ani muscle; obstetric injuries; obstetric vaginal tear; pelvic floor disorders; perineal tear.