Inverse Finite Element Analysis of the Indentation Response of Human Cervical Tissue

The mechanical function of the cervix is crucial during pregnancy when it is required to resist the compressive and tensile forces generated from the growing fetus. Pathologies of the cervical extracellular matrix (ECM), premature cervical remodeling, and alterations of cervical material properties have been implicated in placing women at high-risk for preterm birth (PTB). To understand the mechanical role of the cervix during pregnancy and to potentially identify etiologies for PTB, the overall goal of our group is to quantify ECM-material property relationships in normal and diseased human cervical tissue. In this study we present an inverse finite element analysis (IFEA) that optimizes material parameters of a viscoelastic material model to fit the stress-relaxation response of excised tissue slices to spherical indentation. Here we detail our IFEA methodology, report viscoelastic material parameters for cervical tissue slices from nonpregnant (NP) and pregnant (PG) hysterectomy patients, and report slice-by-slice data for whole cervical tissue specimens.