A model and simulation of uterine contractions

We present a model of uterine contractions that consists of tissue mechanics, electrical activity, and intrauterine pressure. Uterine contractions were simulated to measure the impact that +/- 3% changes in mechanical and electrical properties have on peak intrauterine pressure and the duration above 90% peak pressure. Peak pressure was overwhelmingly affected by changes in one mechanical property (maximum stress generated from cellular contraction), whereas duration above 90% peak pressure was overwhelmingly affected by changes in two electrical properties (the recovery rate and activation threshold of the action potential). In contrast, changes in other properties (e.g. pacemaker location and diffusion coefficient) had an impact on intrauterine pressure one order of magnitude smaller. Additionally, intrauterine pressure was strengthened by decreasing the fraction of fasciculi aligned in the longitudinal rather than the circumferential direction.