The effect of uterine fibroid region and depth on endometrial stress and strain: a finite element approach

Uterine fibroids are common benign gynecological tumors that are observed in up to 80% of premenopausal women. It is understood that as the fibroid size increases, the surrounding tissues will be subject to greater loads. However, the effect of fibroid region on the uterine structure is not as clear. To better understand the mechanical loading of the endometrium due to the presence of a uterine fibroid, we developed a finite element model of the uterus to examine the effect of both fibroid depth and region in relation to the endometrium. The finite element model of the uterus, endometrium, and a uterine fibroid were created from a 3D segmentation of a patient's magnetic resonance images. This model was then loaded into ANSYS Mechanical 2023 R1, and then deformation, stress, and strain of the endometrium was measured for 24 fibroid positions (8 regions × 3 depths). The highest endometrial loads (deformation, stress, strain) were observed when the fibroid region was superior to the uterus and the depth was deep. Superior regions generated 10-20% higher loads on the endometrium in comparison to other regions, while deep locations had 5-10% higher endometrium loads when compared to superficial depths across almost all regions. A simple uterus model was used to show the effect of fibroid position on loads acting on the endometrium. This can provide insight into mechanisms of abnormal uterine bleeding and infertility and better inform clinical decision making.