Cervical remodeling in term and preterm birth: insights from an animal model

Proper cervical function is essential for a normal pregnancy and birth to occur. Understanding the mechanisms that take place in normal pregnancy will allow a better comprehension of the complications involved in premature cervical remodeling and lead to better methods of diagnostics and prevention for preterm birth. Unfortunately, human samples are not easily available, and samples that are collected are often confounded by variations in timing and region of cervix from which sample is collected. Animal models, specifically the mouse, have facilitated a great deal of exploration into the mechanisms of cervical function and pathways of preterm birth. This review highlights some of the groundbreaking discoveries that have arisen from murine research including 1) the identification of early pregnancy changes in collagen fibril processing and assembly that result in progressive modifications to collagen architecture with subsequent loss of tissue stiffness during pregnancy, 2) the determination that immune cells are not key to cervical ripening at term but have diverse phenotypes and functions in postpartum repair, and 3) the finding that the process of preterm cervical ripening can differ from term ripening and is dependent on the etiology of prematurity. These findings, which are relevant to human cervical biology, provide new insights that will allow targeted studies on the human cervix as well as identify potential biomarkers for early detection of premature cervical ripening and development of improved therapies to prevent premature ripening of the cervix and subsequent preterm birth.