Transperineal Three-Dimensional Ultrasound Combined with Real-Time Shear Wave Elastography Imaging to Assess Changes in Pelvic Floor Structure During Pregnancy and Delivery

Background: Pelvic organ prolapse seriously affect women's physical and mental health. To quantitatively analyze the structure of the pelvic floor during pregnancy and delivery, we utilized transperineal three-dimensional ultrasound (TP-3DUS) imaging combined with real-time shear wave elastography (RT-SWE). This analysis aims to provide exploratory data on female pelvic floor parameters, such as the hardness and thickness of the levator ani muscle (LAM), and to offer personalized recommendations for the prevention and treatment of early clinical pelvic organ prolapse (POP). Methods: From March 2021 to August 2022, a study was conducted at the Affiliated Hospital of Yunnan University involving 150 pregnant patients at various gestational ages, 110 primiparas at 42-45 days post-delivery, and 55 healthy non-childbearing women. RT-SWE was used to quantitatively evaluate changes in the elasticity of the puborectalis muscle (PRM), while TP-3DUS imaging was used to measure various parameters of the pelvic floor. This study investigated changes in pelvic floor structure during pregnancy and postpartum. It evaluated the efficacy of PRM elasticity, levator hiatus (LH) area (LHA), and the thickness of the LAM, along with their combined application in diagnosing early postpartum POP. Results: As gestational weeks progress, the elasticity of PRM increased, while the thickness of LAM decreased. In the control group, cesarean section group, and vaginal delivery group, the elasticity of the PRM and the thickness of the LAM progressively decreased. The area, perimeter, LH anteroposterior (LHAP) diameter and LH lateral diameter (LHLD) increased sequentially in these groups. The combination of LHA, PRM elasticity, and thickness of the LAM in both vaginal delivery and cesarean section groups demonstrated the highest diagnostic efficiency for POP. Conclusions: The combination of TP-3DUS Imaging and RT-SWE represents a novel, effective, and convenient method for evaluating the structure and muscle elasticity of the pelvic floor during pregnancy and the early postpartum period. LHA, PRM hardness, and thickness of the LAM individually possess a diagnostic value for early postpartum POP. However, their combination yields the highest diagnostic efficiency.