Behavioral analysis of perineal tissue during childbirth: development of a patient-specific model [English translation]

Perineal tears, regardless of their severity, can be a source of physical and psychological morbidity in the immediate postpartum period and in the long term. Such injuries are experienced by approximately 60% of all women. To date, the occurrence of a perineal tear during childbirth remains unpredictable and is still poorly understood from a biomechanical perspective. The overarching objective of this thesis was to improve our knowledge of the biomechanical behaviour of the perineal tissues during childbirth and to obtain their biomechanical properties through three complementary approaches. The initial approach was experimental and ex vivo. The mechanical properties of the porcine perineum were investigated using uniaxial tensile tests, elastography and stereophotogrammetry in the basal state, then during deformation with a balloon pulled through a porcine vagina, which was used to simulate the processes occurring during childbirth. The second approach was clinical. An exploratory clinical trial was conducted to study in vivo the mechanical properties and deformation of the perineum during pregnancy and childbirth using elastography and stereophotogrammetry in pregnant women. The third approach was numerical. All the mechanical data obtained from imaging and clinical measurements were incorporated into a numerical model.