 Accordingly, CL is now widely used in clinical practice for risk estimation. Crane et al., 1997 However, as understanding of the mechanisms of preterm labor PTL have evolved, obstetricians have learned that, in some women, cervical shortening is a phenomenon that carries no increased risk for prematurity. Therefore, the search for early and accurate markers that distinguish between physiologic processes and abnormal activation of the labor cascade has been ongoing. 