Volume sonography of the pelvic floor in nulliparous women and after elective cesarean section

Objective. To describe the sonographic appearance of the pelvic floor which has not been stressed by forces of labor or vaginal delivery in pregnant women and after childbirth. Subjects and methods. In a prospective observational study 14 nulliparous women during first trimester pregnancy and 26 primiparous women after elective cesarean were examined within the first week postpartum. The integrity of the internal anal sphincter expressed as the ratio between the anterior and the posterior internal anal sphincter muscle thickness (alp-ratio), asymmetry of the levator ani muscle and the paraurethral fixation of the lateral vaginal edges at the arcus tendineus were assessed using volume sonography. Results. The alp-ratio in nulliparous women was significantly higher (p <0.01) than after elective cesarean section. Asymmetry of the levator ani muscle did not differ between both groups but was more frequently in the nulligarous patients with an odds-ratio of 1.16 (CI 0.74-1.82). In both groups of women the paraurethral fixation of the lateral vaginal edges were above the suburethral level of the vagina. Conclusions. This study gives sonographic features of the pelvic door in nulliparous women and in primigravidae after elective cesarean section. Data from the post-cesarean group can serve as reference values for further studies evaluating pelvic door damage after various modi of vaginal delivery.