Advanced FE simulation coupled with statistical surrogate modeling toward a multifactorial view on the pelvic floor muscle damage and perineal tearing during childbirth.

Vaginal deliveries are frequently associated with perineal trauma, including severe tearing in some cases. Understanding of pelvic floor muscle damage and perineal tearing during childbirth is of great clinical relevance. However, the knowledge of these complex phenomena is incomplete. The objective of the present study is to explore the multifactorial view of pelvic floor muscle damage and perineal tearing during childbirth. Using nonlinear finite element modeling coupled to statistical surrogate modeling, we modeled fetal descent with imposed displacement and used active maternal for muscle contraction to estimate the pelvic floor muscle damage and perineal tearing indicators under different influencing factors such as fetal head deformability and biometry, as well as constitutive behaviors. The obtained results show that fetal head deformability reduces stress and strain concentrations in the pelvic floor muscles (PFM) and perineal region, while increasing fetal head size leads to heightened internal tissue responses. Linear regression analysis demonstrated strong model performance (R² = 0.782-0.981) and statistically predictive relationships between fetal biometric parameters, soft tissue constitutive behaviors, and associated mechanical responses. By integrating advanced finite element modeling with statistical modeling and regression, this work provides new quantitative insights into the biomechanical factors, highlighting tissue deformation patterns and indicating potential risk of tissue damage in highly strained areas due to localized mechanical stress. This approach offers a predictive and non-invasive strategy for assessing maternal tissue vulnerability during childbirth.