The influence of the material properties on the biomechanical behavior of the pelvic floor muscles during vaginal delivery.

In this work, a finite element model intends to represent the effects that the passage of a fetal head can induce on the muscles of the pelvic floor, from a mechanical point of view. The finite element method is a valuable tool, that is contributing to the clarification of the mechanisms behind pelvic floor disorders related to vaginal deliveries, although some care is necessary in order to obtain correct results. The present work shows how the variation of the material parameters, used in the constitutive model, can affect the obtained results from a finite element simulation. The constitutive equation adopted in this work for the pelvic floor muscles is a modified form of the incompressible transversely isotropic hyperelastic model proposed earlier by Humphrey and Yin. Results for the pelvic floor strain and stresses obtained during the passage of the fetus head are presented. The results show the importance of the material parameters and the need for a correct constitutive model.