2019 Conference Objects and Reports

Anisotropic material properties of the human uterus

Fang, Shuyang; McLean, James Patrick; Vink, Joy-Sarah Yumiko; Hendon, Christine P.; Myers, Kristin M.

The mechanical function of the uterus is crucial for the protection of the fetus during a healthy pregnancy. Early contractile activation of uterine tissue can lead to preterm labor and birth (PTB). In 2014, 9.56 percent of pregnancies ended in PTB; it is also the leading cause of death in children under five years of age. Characterizing the material properties of uterine tissue is important for understanding the mechanical failures of the uterus and the causes of PTB. In this study, a workflow of experiments and data processing techniques were employed. 78 uterine specimens were collected from consenting 28 patients who underwent hysterectomy. A four-level ramp-hold indentation test was performed. IFEA was performed to fit four material parameters to the experimental data: Young's Modulus E, Poisson’s ratio v, the fiber stiffness factor ksi, and the fiber angle concentration b. Within each uterus, significant differences in Young’s Modulus E and Poisson’s ratio n were observed at different locations and different layers, indicating the heterogeneity of the human uterine material properties. However, the fitted values for fiber stiffness x and angle concentration b exhibited a wide spread with no significant differences observed across comparison groups. There were also no obvious differences between patients with different parities, as suggested in previous studies.