ISOTROPY AND ANISOTROPY OF UTERINE MUSCLE DURING LABOR CONTRACTION

A strain rosette analysis performed on 36 women during their 36-42 weeks of pregnancy at various points over the fundal region, shows that the functional performance of the uterine muscle is anisotropic in its character and a kinematic isotropy is a good approximation only during the early stages of labor. The various groups of fibers exhibit different viscoelastic properties, with the longitudinal group showing more resilience than the others. A case which proved an exception was that of an eighth month delivery showing the reverse behavior of strain hardening.